Fix JavaScript Button test for IE 7+8

The order changes in IE, causing buttons that were not disposed to
influence the following tests.
Allow browser native context menu on links

Like on text fields, the browser context menu now can be used on links
that are embedded in widgets that have no SWT context menu of their own.
Links with target="_rwt" are excluded.

See also Bug 406199 - Add a way to re-enable selectable content and
browser context menu
Revert "fix" for text value of Hyperlink selection events

This reverts "Fix red JavaScript test in IE8", commit
acf5a6e10b0827b739f04f8212134d3c2b49ebfb.

If a URL was put into the "href" attribute, the protocol was cut off.
Update JavaScript tests for RWT hyperlinks to tolerate URL rewrite

Also updated the JavaDoc to warn about these rewrites
Fix html element offset calculation in Opera

Modern versions of opera have to use the same method as webkit and IE.
See Bug 403727 - [Combo] Drop down list misaligned after parent scroll
in Opera
Remove org.eclipse.rap.rwt.jstest test from build and SDK feature
Enable tests when running a signed build

- Remove skip tests property in SIGNPROFILE
  -Dmaven.test.skip=true
Move surefire tests into integration-test phase
Fix error in Tycho/Maven goal of RAP Runtime build
Revert build configuration changes due to signing problems
Add ClientMessages service for client messages localization

Render localized client messages in startup JSON message (for WebClient
only).
When locale is changed the localized messages will be updated on the
client.
Shutdown dummy UI session created in the GET request after processing
it.
Update Tycho build configuration to RAP 2.1 RC1

- Prepare for Kepler RC1
- Update target to Eclipse Platform S-4.3RC1-201305162200
Redesign client error box
Fix client error box layout in IE8
Use localized massages for client-side errors
Style error box hyperlink as button

Return empty string if client message is missing
Align error box text color with RAP default theme
Fix JavaScript tests on MacOS Safari 6
Prevent application crash by float-point mouse coordinates

Mouse coordinates are already rounded in the client mouse event wrapper. 
Bug 408701 - IllegalArgumentException: "Not a valid integer number" when
browser zoom < 100%(IE10)
Rebuild client.js