package.json: add a repository field

NPM kept complaining about this repository field missing.
package.json: use devDependencies throughout

None of the dependancies listed are actually required for *using*
TinyMCE, but merely when building it. The distinction is mainly an
issue of clarity and correctness, as TinyMCE isn't used as a Node
package proper.
package.json: prevent publishing of TinyMCE to NPM

NPM isn't a node package as such, and thus isn't terribly useful as a
dependancy. As a result, it probably shouldn't be published to NPM,
and this flag prevents it.
Fixed bug where WebKit/Blink would scroll to the top of editor if the height was more than the viewport height.
Fixed a but where WebKit/Blink clones elements when images are floated.
Merge pull request #307 from danchr/package-json

Minor tweaks to ‘package.json’
Added text-shadow css attribute to the preview styles list
Fixed so the old mceSpellCheck command toggles the spellchecker on/off.
Merge pull request #312 from nhammadi/master

Added text-shadow css attribute to the preview styles list
Fixed so the setupeditor event is fired before the setup callback setting to ease up compatibility with 3.x.
Synced the compat3x plugin with the wp version.
autosave plugin stores content only if it was really changed #6629
Fixed bug where the tabfocus plugin would prevent the user from suing Ctrl+Tab, Patch contributed by Andrew Ozz.
Fixed misspelling of aria-labelledby attribute.
Merge pull request #315 from stevenbg/master

autosave plugin stores content only if it was really changed #6629
Fixed potential crash with lastFocusBookmark during focusin event
Fixed issues when you try to switch state after an control has been removed.
Fixed bug where image selector formats wasn't properly handled by the importcss plugin.
Fixed so you don't need to set language option to false when specifying a custom language_url.
Fixed bug where the dirty state of the editor wasn't set when editing an existing link URL.