Changes

Bug 548128 - SWTBot Nattable extension should not depend on Eclipse

SWTNatTableBot now derives from SWTBot instead of SWTWorkbenchBot. Also
removed imported package eclipse.ui. Thus there is no eclipse
dependency.

Two additional constructors are provided for SWTNatTableBot which accept
another SWTBot and parent widget.
This will enable the user to search on specific
view/editor/shell/widget, etc.

The same change is done for all other nebula Bot classes- SWTNebulaBot,
SWTCheckBoxGroupBot, SWTRangeSliderBot, SWTStepbarBot.

Major version of SWTBot is changed to 4.0 since this could be an API
break for some users who could possibly be using these bots to find
Eclipse views or editors, etc.
SWTBot version is changed from 3.2.0-SNAPSHOT to 4.0.0-SNAPSHOT in all
places.

Change-Id: I552f77355b1af769f511ac9cbfce32606444345a
Signed-off-by: Aparna Argade <aprsac@yahoo.com>

Fix swtbot-tycho to get snapshots repo, update eclipse-jarsigner-plugin

Update eclipse-jarsigner-plugin to 1.3.2 in pom.xml

swtbot-tycho jenkins job is failing with error "Failed to execute goal
org.eclipse.cbi.maven.plugins:eclipse-jarsigner-plugin:1.1.3:sign"

Change-Id: Id9d7b493513a716d50c83dba6ebf4a07bea047c6
Signed-off-by: Aparna Argade <aprsac@yahoo.com>