Fix #4333 (files shown as plain text incorretly).

- Added FileUtils.getBaseName (jsdoc and unit tests included).
- Replace usage of path-utils.js with getBaseName.
Fix unit tests for FileUtils.getBaseName.
Add support for project-wide JSLint config.

Related to issues #3269, #4210.
Based on the discussion and suggestions in #3310.

If a project has a .jslint.json in its root, it gets loaded and passed to each
JSLint run within the project. The configuration file gets reloaded each time
it is saved or refreshed.
Revert "Add support for project-wide JSLint config."

This reverts commit 11dbdfdb5d84ecaee826bd722b1053ede0fba60e.
Animate inline editors open.
clean up from review
Push update/remove management into ExtensionManager
Removes methods that simply delegate to ExtensionManager
Incomplete: pulling the update/remove action into the Dialog.

The tests have not yet matched the refactoring, but the idea is
to have the extension manager dialog trigger the update/remove
functionality, rather than the individual views.
Added missing file extensions for C# web dev
Find In Files on an untitled document should initiate a Find session in that document
Fix CSSUtils unit tests.

The tests assumed that CodeMirror modes are loaded at the time of test
definition.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/file/FileUtils.js
Fix Editor tests.

LanguageManager.getLanguageForPath should not use URLs. Instead, it
should use local filesystem paths.
Removed excessive : from the test description.
Add getFileExtension implementation and unit tests

Also:
Remove leftover reference to LanguageManager from FileUtils.
Use existing code to implement getBaseName.
Get rid of PathUtils where appropriate.

Implementation changed to use FileUtils.getBaseName and
FileUtils.getFilenameExtension.
Remove stale jslint PathUtils refs and extra loads
Restore jslint config to include PathUtils.
Addresses review comments and detects updates.