Make ASCII escape characters optional. Colored output can be deactivated with
`--plain` or the environment variable `DOXEC_COLOR=0'. The environment variable
can be overridden with `--color`.

Resolve "Make <pre> </pre> also valid block boundaries in Markdown"

Closes #6

See merge request !3

Add a short remark in the README about pre-tags as code block delimiters.

Implement the new Markdown syntax, such that code blocks can be bounded by
<pre> and </pre>.

Closes #6.

Add tests to ensure that block delimited by <pre> and </pre> are parsed
correctly and do not interfere with the old syntax.

Since the code example is enclosed in the HTML tags <pre>, the command line
comment tag has to be escaped.

Update the console output in the example in order to match the output generated
by the improved version 0.2.0.

Feature/improve output

Closes #3

See merge request !2

The new version has an improved user interface.

Add comments explaining the behavior in execute() and run() methods, since the
logic might be a bit hidden due to the monitor design.

Add the name of the program 'Doxec' to the copyright line in the print out.

Improve the messages displayed to the user including the following changes:
 - Using ascii escape codes to use colors
 - Print file name and line numbers
 - Use str(operation)
 - Print summary at the end
 - Define monitor interface
 - Add copyright output
 - Print standard out of operations
 - Add short option to suppress operation standard out

Closes #3.

The default monitor class is currently not tested.

Bug/return code

Closes #4

See merge request !1

Fixing bug #4 leads to this increment.

The return code of the doxec script reflects the number of files, which failed
during execution. Fixes #4.

Fix minor typos in the README and the hello world tutorial.

Add a README document with basic installation and use instructions. Ironically
doxec is not used on this piece of documentation.

Don't enforce the end comment characters --> in markdowns command line. This
closes #2. The new implementation however, enforce that > is not used in
neither the command nor the args.

Implement the doxec executable. In order to use nice callbacks between document
run() and doxec, a monitor function has been introduced.

Implement the document class which functions as an entry point. This constitutes
the last puzzle piece of the doxec package.

Implement the operation console_output, which runs the listed commands and check
that the output matches.

Implement the operations write, append and console including unittests for all
execute methods.

Add unittests for the base class Operation. The tests focus on the static
factory method. This method has already been implemented.

Implement all parsing methods for Markdown syntax, such that all test
requirements are satisfied.

The commit provides a functioning CI and therefore closes #1.

Adds unittests for DoxecSyntax subclass Markdown. The implementation of these
tests lead to slight modifications in the doxec package. The DoxecSyntax.parse
expects a list of lines, which is modified in place, instead of a plain string.

Create an empty package named doxec.tests to store all unittests.

Fix mistakes indicated by previous pipeline. The errors arise from missing
imports or plain syntax errors.

Add gitlab-ci configuration using the attached docker image using ubuntu 16 and
python3. The CI consists of two test jobs: unittest and doctest

Add the `.gitignore` file containing wildcards for temporary vim files and the
python cache directory.

Adds skeleton classes for dexec package. Most classes define only a list of
methods, without implementation, but a short comment about its purpose. As of
now, the list of classes and methods, seems to be sufficient. The package lacks
unittests and the CI setup.