Put downloaded files in public download directory.

It's probably more expected having them in /sdcard/Downloads instead of
/sdcard/Android/data/com.gh4a/files/Download.
Fix typo breaking download in Gingerbread.

DownloadProvider threw a SecurityException, because "true" (the string)
does not equal true (the boolean).
Merge pull request #205 from maniac103/for-upstream

Download fixes
Close #199
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Merge pull request #206 from maniac103/for-upstream

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Feature to add a comment on the line
Edit and delete comment on the line
Confirm before delete comment and UI improvements
Feature to add a comment on the line
Refactor create dialog builder
Simplifications & optimizations.
String improvements.
Improve comment dialog behaviour.
New "Files" tab at pull request and tidy up commit comment and review comment
Refactor file viewer classes
Combine comments and review comment in pull request conversation
Resolve conflict