Fix #34.

When using nested Maven projects with M2E, it seems M2E does not
properly indicate files belonging to subprojects as filtered from
the parent project. As a result, if we called
IWorkspaceRoot.getFileForLocation(path) to resolve the location
of a resource, it would typically return a IFile referring to the
file through the parent project instead of the expected
subproject. This would then end up opening files in Eclipse
appearing to belong to the "wrong" project (when "Link with
editor" is active) when following a hyperlink.

To work around this, we instead fetch ALL possible IFile
references for the given path and try to pick the best one using
heuristics.
Users have verified that it is ok to use variables in SETTING_FILE tokens
Extract proposal list calculation to separate class
Use ResourceManager through new IResourceManager api for better testability of other classes using it
Fix #35. Logic for determining which files still need to be visited failed to account for files already enqueued to be visited. Unit tests added.
Issue #23 implemented to the extent that it excludes imported variables from proposals in variable table.
Fix #23 completed.

Now limits proposals further by:
 - in Variables table only proposing variables declared earlier in the file
 - in Settings table only proposing variables declared in the file or in resources/libraries imported earlier in the file
Issue #43 integration test

Conflicts:

	src/test/java/com/nitorcreations/robotframework/eclipseide/internal/assistant/TestProposalGenerator.java
Eclipse feature and update-site projects
Added update-site generated binaries to gitignore
Fix #43. Reviewed and improved variable replace region logic. Unit tests added.
Add more unit tests and clean up
small refactor
rename
Add missing keyword-taking-keyword-as-argument
Bump version to 1.0.7
Improve Robot IDE presense during installation and in About dialog.

- Eclipse About dialog: add robot icon button, which shows "Nitor Creations Oy" when hovered. When clicked, opens a dialog showing the Robot IDE feature overview.

- When Robot IDE feature is shown (i.e. during installation, or when about robot button clicked, or when browsing features in About -> Installation details -> Features), show same robot icon and feature description.

- Improved feature description to include Robot IDE homepage link and copyright.
Move feature description, license and copyright to separate file
Move plugin to a subdirectory to make importing & management easier.
Unify project names