Main activity, minor changes

* Main activity with description and links
* Decrease MAX_UPDATES_BEFORE_COMMIT to 25 (may fix #25)
better vcard parsing error logging, always append trailing slash to collection URLs
don't follow redirects (see issue #52)
Version bump to 0.3.6

* show app version in main activity
improved photo parsing, DELETE statement

* let ical4l-vcard do the photo parsing; tested with posteo, OwnCloud,
eM Client; fixes #53
* improved DELETE statement to avoid
"android.database.sqlite.SQLiteException: Expression tree is too large"
(fixes #54)
* added "file name required" validation
iCal4j update, handle relative URLs with colons

* iCal4j 1.0.5 -> 1.0.5.2, iCal4j-vcard 0.9.5 -> 0.9.6.2
* handle relative URLs with colons in name (see issue 45)
support for structured addresses (closes #29); bug fixes
Version bump to 0.3.7 (version code 11)
Merge remote-tracking branch 'blessed/master'