add merge_assoc() method to Arr class

Force merge to not change integer keys that already exist
added support for collating sequence to db config. closes #1512
Merge pull request #1510 from sagikazarmark/1.7/develop

Bootstrap 3.0 upgrade
Merge pull request #1508 from propcom/feature-array-merge-assoc

Add merge_assoc() method to Arr class
made the use of URI wildcards configurable; closes #1490
allow the creation of nameless fieldsets. closes #1487
added has_connection to check for a valid DB connection; fixes #1264

if no connection was present, connection() would try to connect again,
causing the original exception to be lost.
added unit test for Arr::merge_assoc()
added Arr::reindex to reindex indexed arrays
fixed cockup in dealing with charactersets. closes #1513, #1514
avoid an exception when calling put/patch/delete on a get or post request
reset the main request too if there is no active parent
make resetting the main request optional
fix $main not being available in lazy view rendering. closes #1519
do not try to fetch the active's parent if there is no active request
reverted old behavior of allowing a collating sequence to be passed as charset. Closes #1522
charset SQL sequence fix. closes #1524
cleanup of Mongo exceptions; pass Mongo exception code back on caught exceptions. closes #1525
swap file_exists with is_file. closes #1520
added option to render() to return the raw data array. closes #1523