FIX postgres can filter on non text fields

Filtering non text fields in postgres would cause the SQL to fail. This
casts the field to text before the LIKE filter.
Fix Versioned::augmentSQL() when the data query was null.
Fixed RSS example
Merge pull request #2654 from icecaster/patch-3

Fixed RSS example
formHtmlContent() uses missing FormEncType() call

it needs to call $this->getEncType() instead..
FIX UploadField validation error and styles

UploadField now return the validator's error message instead of 403. Plus nicer layout for error messages.
Allow GridFields without titles to be found.
Merge pull request #2242 from torleif/3.0

FIX postgres can filter on non text fields
Update install.php5

Defaulting to MySQL here is really dumb. There is an explicit type as an argument so falling back to mysql could result in "I couldn't write to path ....db" despite the real error that the include of the sqlite3/code/SQLiteDatabaseConfigurationHelper.php failed for some reason.

Other uses of getDatabaseConfigurationHelper also need a similar error handler.
FIX Overriding of theme templates in project folder

Fixes issue of templates not being found when a Page's main/Layout templates are split between the project and theme folders. Adds more expansive testing for template loading.
BUG Ensure TreeMultiSelectField doesn't populate menus with "unchanged".
TreeMultiSelectField's default for its value property is 'unchanged'
which causes menus to not load and generates console errors. Fixes #2795
BUG: #2503 Fixes performReadonlyTransformation for OptionSetField

NEW: Adding unit test for performReadonlyTransformation #nd fixing OptionSetField #2503

BUG: Fixing undefined variables and function parameters for PerformReadonlyTransformation unit tests

NEW: Adding unit test to OptionsetField for read only fields
$manifest needs to be global for Deprecation.
Updated add-on URL.
Use filtered file paths in upload (fixes #2836)
Merge pull request #2834 from mattkirwan/patch-1

Updated add-on URL.
Correct JS i18n in UploadField (fixes #2370)
NEW: Forms with invalid/expired SecurityIDs are repopulated (fixes #1891)
BUG Fix missing description element on FieldGroup_holder.ss
Merge pull request #2839 from tractorcow/pulls/3.1-fieldgroup-description

BUG Fix missing Description element on FieldGroup_holder.ss