Support quotes and tabs in general API description

[j0s]

Describe the PR
Handle quotes and tabs in general API description. The two-stage application of templates when generating docs.go, and then applying a template in ReadDoc(), resulted in escaping of quotation mark getting lost. This PR re-adds adds those quotations using a less than beautiful workaround, but at least it works on my test cases.
It also adds a test that compiles the generated file docs.go, runs the ReadDoc() method, and compares the output to a template.

Related issue
#738

Additional context
I stumbled upon this when expanding my documentation using markdown. When writing long descriptions, supporting quotation marks and tabs would be very useful.

[sdghchj]

LGTM

[easonlin404]

@j0s sorry, because ci check had some issue there before. could you help retry the build again? eg: some minor changes

[codecov]

Codecov Report

Merging #743 (a98eccc) into master (19e5237) will decrease coverage by 2.74%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #743      +/-   ##
==========================================
- Coverage   84.83%   82.09%   -2.75%     
==========================================
  Files           8        8              
  Lines        1649     1737      +88     
==========================================
+ Hits         1399     1426      +27     
- Misses        145      193      +48     
- Partials      105      118      +13     

Impacted Files	Coverage Δ
gen/gen.go	95.41% <100.00%> (+0.14%)	⬆️
schema.go	86.74% <0.00%> (-11.98%)	⬇️
parser.go	76.94% <0.00%> (-5.07%)	⬇️
types.go	100.00% <0.00%> (ø)
swagger.go	100.00% <0.00%> (ø)
operation.go	88.46% <0.00%> (+0.79%)	⬆️
packages.go	73.33% <0.00%> (+2.85%)	⬆️
debug.go	50.00% <0.00%> (+30.00%)	⬆️

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[j0s]

Ok, so I fixed a linting error. But the coverage must be caused by codecov not being run for a while right? It's complaining that coverage of parser.go has decreased, but I haven't touched that file?

[j0s]

Is there anything blocking this from being merged, except for the travis job that does not seem to run?

[j0s]

I would still like this to be merged if it looks good to you.

[jecolasurdo]

Any movement on this?