[READY] Add vimspector config

[puremourning]

This allows debugging of ycmd tests directly using vimspector. I use a
mapping which runs the test under the cursor, so one of the variables it
asks you for it "test" which is essentially arguments to nosetests.

NOTE: It doesn't work on windows, and it requires the use of a
virtualenv at the moment. This is mainly due to a limitation of
vimspector that it only has simple variable replacement in its config.

It's actually possible to set variables based on shell commands so if the use of venv is painful for anyone else who actually uses it I can improve that.

Demo:

To use:

• install Vimspector: https://puremourning.github.io/vimspector-web/. enable the HUMAN mappings (or the vs ones if you prefer. or write your own)
• install the python debugger cd /path/to/vimspector; ./install_gadget.py --enable-python
• open a test file and navigate to place to break, hit <F9>
• hit <F5>
• Test should be set to either empty (all tests) or nosetest arg such as ycmd/tests/get_completions.test:<function>
• python_version should be 2 or 3 - this selects the regex module that gets loaded.

I also have a bunch of mappings and a compiler plugin that lets me do this with a single keystroke.

This can all be improved over time if people use it a lot.

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This change is 

[bstaletic]

The configuration works (not that I doubted it), therefore .

[puremourning]

great. let's ship it.

[bstaletic]

Reviewed 1 of 1 files at r1.
Reviewable status: 1 of 2 LGTMs obtained

[mergify]

Thanks for sending a PR!

[codecov]

Codecov Report

Merging #1264 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1264   +/-   ##
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  Coverage   97.46%   97.46%           
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  Files          95       95           
  Lines        7260     7260           
  Branches      153      153           
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  Hits         7076     7076           
  Misses        143      143           
  Partials       41       41

[codecov]

Codecov Report

Merging #1264 into master will decrease coverage by 0.28%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master   #1264      +/-   ##
=========================================
- Coverage   97.39%   97.1%   -0.29%     
=========================================
  Files          95      95              
  Lines        7294    7259      -35     
  Branches      153     153              
=========================================
- Hits         7104    7049      -55     
- Misses        149     169      +20     
  Partials       41      41

[mergify]

Thanks for sending a PR!