This patch adds option to configure custom request content processing logic which gets called before request content is sent to tracker.
Tried to fix st build failure with upgrade of qunit, but that didn't work out well, build failed again  and now with even more errors. Wish I could run the build locally before making more changes, but development environment setup for piwik project is not trivial.
Thanks for the pull request.
Test failed in module externals: 'JSLint' Error: JSLint. Go to: http://jslint.com/ and there you can test that piwik.js code is lint.
jslint issues fixed, unit tests provided. Build is successful, only run on one environment failed because of environment issue as a dependency could not be installed (for more details see https://travis-ci.org/piwik/piwik/builds/28309234 )
Now I see I need another related configuration option - possibility to configure POST request Content-Type header value. Currently it's hardcoded to 'application/x-www-form-urlencoded; charset=UTF-8'
I see I need another related configuration option - possibility to configure POST request Content-Type header value
could you tell me the use case where you want to change the content-type?
Again, environment issues,
Yes you're right all these build failures are random and not caused by your change. We have this issue regularly and we will try to keep minimising the random build failure issue.
The tests you added are nicely done!
With new method one can change request content not to be query parameters string, but a JSON or XML, or something else, and in these cases previously hardcoded form content type header value is not appropriate. So, since content can be customized, IMO content type header should be customizable as well so one can change it to match actual content; having one option without other would be incomplete.
I've made default request method and request content type value DRY, while keeping setters safe. Build is all green.
method was renamed in: https://github.com/piwik/piwik/commit/a0c1fee09a27be27378a82b5eb29c690f03010e4
and documentation updated in: https://github.com/piwik/developer-documentation/commit/bc29074a526662d950a1989d2d4db5b039d1cfad