Consider sym- or hardlinks when comparing files
Remove .sbt root project identification.

In multi-project builds, .sbt files will live at the root of each
subproject, but sbt has to be run from the root to have access to root
project plugins and settings. Eliminating the not null check for .sbt
allows the sbt run to reach the root of the project without bailing out
too early, which would cause ensime-sbt to fail to load from the root of
a project.
Updated Swank protocol documentation
Highlight stack trace with links to code
Updated feature list
Wrap more work in askOption()

All calls to members of type/symbol/tree must take place in the
presentation compiler thread. Without this change we get failures when
trying to inspect types from files that aren't loaded yet.
Merge pull request #352 from edani/pc-race

Wrap more work in askOption()
Merge pull request #335 from jackcviers/remove-sbt-root-identifcation

Remove .sbt root project identification.
Merge pull request #349 from edani/stack

Highlight stack traces
Merge pull request #311 from pashky/master

Symlinks and index
Small updates on current project status