+ re-order displayed metrics based on file-list order

This commit re-orders the displayed metrics "sloc, lint errors, etc" based
on the selected file-list ordering. This is done by moving the appropriate
element via jQuery inside the DOM.

  * update casper-options in Gruntfile
  * add test for "ordered metrics" feature
  * update "plator-sortable-file-list.js" with new sorting feature
  * update "Contributors" in README.md
remove font-awesome-ie7.css links
Performance: calculate chart width only once

For project with 1735 files `drawFileCharts()` in Chrome 33 took ~60s before, and ~20s after that fix.
Adds option to skip empty lines from line count
Performance: deferred chart drawing

Browser tab is unresponsive (entirely frozen) during page load because chart drawing is made synchronously. This patch draws overview and file charts asynchronously, allowing `index.html` page be more responsive right after opening in the browser.
Update plato-overview.js
pass cli option "quiet" through to util.readJSON
message "Could not parse JSON from file" should be suppresses when -q
docs README: fix link in travis status badge
fix ui-test: use pre defined casper instance

As of version `_TBD_` the `test` subcommand pre-defines a _casperjs_ instance
and refuses to execute and exits with:
```
Fatal: you can't override the preconfigured casper instance in a test environment.
```
See also the [Docs](http://docs.casperjs.org/en/latest/testing.html#test-command-args-and-options)

_Note:_
There is currently no _"casper options" support so the tests were executed
with the default settings of _casperjs_.
chore ui-test: enable casper task in `$ grunt test` and update options
refactor ui-test: rewrite test overview page
chore deps: update grunt-casper to 0.3.7
chore deps: satisfy dependencies for $ grunt watch

Add 'grunt-contrib-watch' module as dependency to package.json
and load the task in Gruntfile.js
+ remove deprecated casperjs option and update log-level
Update JSHint to the latest version.
Merge branch 'pr-feature-sortable-metrics' of https://github.com/davidlinse/plato into davidlinse-pr-feature-sortable-metrics

* 'pr-feature-sortable-metrics' of https://github.com/davidlinse/plato:
  + remove deprecated casperjs option and update log-level
  + re-order displayed metrics based on file-list order
Merge branch 'davidlinse-pr-feature-sortable-metrics'

* davidlinse-pr-feature-sortable-metrics:
  + remove deprecated casperjs option and update log-level
  + re-order displayed metrics based on file-list order
Merge branch 'master' of https://github.com/jraller/plato into jraller-master

* 'master' of https://github.com/jraller/plato:
  remove font-awesome-ie7.css links
Merge branch 'jraller-master'

* jraller-master:
  remove font-awesome-ie7.css links
Merge branch 'patch-1' of https://github.com/victor-homyakov/plato into victor-homyakov-patch-1

* 'patch-1' of https://github.com/victor-homyakov/plato:
  Performance: calculate chart width only once