[FIX] replace exception handling with proper check

in ff centroided the precondition of findNearest was handled by adding
a try/catch around it instead of properly checking the pre-condition
itself. this commit replaces the try/catch with a corresponding check
[TEST] CubicSpline2d eval() at input nodes tested
[FIX] fixed try/catch misuse for findNearest also in MassTraceDetection
[FIX] addendum to 8fef18dda7b904850981f303ec5964eb5826a5b2 (findNearest - try/catch - fix)
Merge pull request #911 from aiche/fix/ff-centroided-exception-miuse

[FIX] FFCentroided replace exception handling with proper check
[INTERN] lower bound index fixed
[DOC] comments added
Merge pull request #914 from lars20070/fix/CubicSpline2D

[FIX] fixed index computation in CubicSpline2d::eval and CubicSpline2d::derivatives
fix MSVC warnings (mostly pragma); new IDMapper method for featureMaps; O(n) mapping for IDMapper::annotate (O(n*n) before)
better documentation of IDMapper internals
Merge pull request #916 from cbielow/AMT

[FEATURE,BUILD] IDMapper extension for featureMaps, IDMapper speed improvements, small build system fixes