fixed #508: Eclipse project name != bnd project name,
NullPointerException occurs. 
http://github.com/bndtools/bndtools/issues/issue/508

Squashed the NPE, but doesn't address deeper issue of project -> bnd
name mapping.
fixed #519: Add/Remove Bndtools Project Nature actions should be
contributed to Configure menu 
http://github.com/bndtools/bndtools/issues/issue/519
Partial fix for #582: -runrequires doesn't appear to support
substitution 
http://github.com/bndtools/bndtools/issues/issue/582