Fixed parsing of ocamldep output for post 3.12 versions.

ocamldep version 4.01 adds an extra space to its output that causes OcaIDE to try to use a file named ":"

diff 3.12.assert.ml-deps 4.01.assert.ml-deps 
1,2c1,2
< assert.cmo: assert.cmi
< assert.cmx: assert.cmi
---
> assert.cmo : assert.cmi
> assert.cmx : assert.cmi

This results in the mysterious error message: "Path must include project and resource name: /:"

This patch fixes the problem while retaining backward compatibility by ignoring any file named ":" when parsing the ocamldep output.