Avoid searching binary files; tweaks to language mappings; APIs to unregister file extension mapping

* Recognize a wider variety of HTML templates embedded in script tags (e.g., as seen in http://forums.adobe.com/message/5796140#5796140)
* Remove generic "clike" language declaration that no files map to - seems unneeded, and clutters the dropdown in PR #6409
* Add missing commenting syntax to Scala language
* Automatically filter out a variety of common binary file types from Find in Files (it already checks isBinary) - note that this does not affect Mac, where all binary file IO fails automatically. Helps reduce bugs like #6091. 
    * This is basically a head start on https://trello.com/c/JwRiuOwX/1139-1s-automatically-ignore-exclude-binary-files
    * I left the `ProjectManager.isBinary()` API in place for now, since it also excludes files from Quick Open and other getAllFiles() clients that don't yet check isBinary via LanguageManager the way Find in Files does.  When we get to the real user story we should fully eliminate it, though.
* Fix incorrect code in Find in Files that only narrowly avoids creating bugs where filtered-out files are incorrectly added to search results.