Dynamically import modules of extensions

[ayan-b]

Related to #90

Before raising the PR, here is a check list:

1. have you written unit tests for your code changes?
2. have you run "make format"?
3. are you requesting to "dev"?
4. have you updated the change log?
5. do you think that you can understand your changes after 6 month?
   5.1) can someone else understand your changes without your explanation?
6. are you pround of your code changes?
   6.1) do you have the feeling of achievement?
7. please add your name and github link to contributors.rst in alphabetical order.

[ayan-b]

Adding tests.

[codecov-io]

Codecov Report

Merging #229 into dev will decrease coverage by 0.12%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##              dev     #229      +/-   ##
==========================================
- Coverage   99.28%   99.16%   -0.13%     
==========================================
  Files          57       57              
  Lines        2251     2271      +20     
==========================================
+ Hits         2235     2252      +17     
- Misses         16       19       +3

Impacted Files	Coverage Δ
tests/test_docs.py	100% <100%> (ø)	⬆️
tests/test_engine.py	100% <100%> (ø)	⬆️
moban/jinja2/engine.py	100% <100%> (ø)	⬆️
tests/test_reporter.py	98.33% <0%> (-1.67%)	⬇️
moban/mobanfile/__init__.py	97.63% <0%> (-1.58%)	⬇️

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[chfw]

Do we care about the return values of imported module?

[ayan-b]

Do we care about the return values of imported module?

No, I guess. If we only import, that'll do the job.

[chfw]

So we just remove globals thingy then we are good to go

[chfw]

Can you update the docs where jinja2 extension used? Put an example to use jinja2 time module so that we are covered on integration and regression tests . Meanwhile, we got a bit more docs.

Last thing, please update changelog.

[ayan-b]

In order to use jinja2_time, we need to finish #202 (Ref). Instead, I am writing the docs using https://pypi.org/project/jinja2-python-version/ .

[chfw]

OK. Will merge now. Please remember to update the docs :)

[chfw]

change log, change log update please.

[chfw]

good use of set.

[ayan-b]

In order to use jinja2_time, we need to finish #202 (Ref). Instead, I am writing the docs using https://pypi.org/project/jinja2-python-version/ .

Tried using jinja2-python-version, but it seems it does not support Python 2 and pypy.

Related build: https://travis-ci.org/ayan-b/moban/builds/495392863

[chfw]

Good to go!