bump DB version to 20

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@769 70aa8380-c310-11de-8ec6-755e00613368
Version 1.7.5.2

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@770 70aa8380-c310-11de-8ec6-755e00613368
Minor cleaning.

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@771 70aa8380-c310-11de-8ec6-755e00613368
workaround for concurrent Bixi DB access

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@772 70aa8380-c310-11de-8ec6-755e00613368
Using view-holders in list-view adapters.

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@773 70aa8380-c310-11de-8ec6-755e00613368
fix NPE

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@774 70aa8380-c310-11de-8ec6-755e00613368
this should fix all concurrent issue with the Bixi data

git-svn-id: http://montrealtransit-for-android.googlecode.com/svn/trunk@775 70aa8380-c310-11de-8ec6-755e00613368