JBIDE-15111 Bad text formatting when inserting JS/CSS

Added using preferences/settings of the editor to insert space symbols (N spaces/tab) instead of hardcoded " ".
JBIDE-15263 Create Datasource Dialog/Wizard usability

Wizard is moved to category 'JBoss Tools'.
Default value for 'Format' input is changed to 'AS 7'.
Default value for 'Register' input is changed to 'false'.
JBIDE-15321 ConcurrentModificationException in KbBuilder

Required synchronization is added.
JBIDE-14591 https://issues.jboss.org/browse/JBIDE-14591

Implemented categories for Properties view for html elements.
[JBIDE-14591] fix for API compatibility issues

Changes are:
* org.jboss.tools.jst.web.ui.palette.html.wizard.HTMLConstants marked as depecated
* ItemsEditor shouuld implement both new and deprecated HTMLConstants to avoid API tooling problems
* JQueryConstants shouuld implement both new and deprecated HTMLConstants to avoid API tooling problems
[JBIDE-14591] service version updated because API changes

3.5.0-SNAPSHOT => 3.5.1-SNAPSHOT
JBIDE-15384 content assist for filenames in html for JBT 4.1.1
JBIDE-15439 updated parent pom.xml
JBIDE-15458 fixed test failure in org.jboss.tools.jst.css.test.jbide.InputFractionalValueTest_JBIDE4790
JBIDE-15378 Basic content assist for static AngularJS ng-* attributes
Set parent pom to Alpha2