Fix line endings and remove random trailing spaces

I've fixed the line endings of all text files, removed random trailing spaces and restored .gitattributes to perform line ending unification on text files.

Currently, there is a huge variety of line endings in this project.  There are LFs, CRLFs, and CRs, and sometimes several within a single file.  This makes it difficult or annoying to handle in many text editors, and something that I dislike.

It also prevents tinymce from being incorporated into other git repositories that enforce line endings, such as git repositories of web site source code.

I've tried running a parallel branch with fixed line endings, but every time code is checked into the master, git reports that every line has changed, making merging very time consuming.

Please move to a uniform line ending, and enforce it for new commits from now on (using .gitattributes).  I see there was a brief start to this on August 3.  Please take the plunge and move all files to a uniform line ending.