add retrieveFeatureData for Tags to util::dataAccess
add retrieveFeatureData for MultiTags in util::dataAccess
add test for feature data access
etended test to check for data access of tags that point to slices
[test] Benchmark: Fix GeneratorBenchmark's id

It is 'G' not 'P'.
[test] Benchmark: Add raw disk IO estimator
Merge pull request #391 from gicmo/bench_disk

Bench disk
TestDataAccess: initials for feature data for multiTags
add retrieveFeatureData method to MultiTag
add retrieveFeatureData method to Tag
rename of method parameter for consistency
minor spelling corrections in exception texts
bugfixes in dataAccess.retrieveFeatureData
finished test for retrieveFeatureData for MultiTags
fix of uninitialized stack allocation
[test] Benchmark: use int distribution for int RNG
[test] Benchmark: use numeric_limits for rng limit

For the int case that is.
[test] Benchmark: Use template param in speed_test
[test] data_type_dispatch: use rvalue ref. for <F>
Merge pull request #393 from gicmo/bench_fixes

Small fixes to benchmarking code