added bwt option to testcase.config
Merge branch 'benchmark_wt' of https://github.com/xosh/sdsl-lite into benchmark_wt

Conflicts:
	benchmark/wavelet_trees/test_case.config
	benchmark/wavelet_trees/wt.config
fixed a bug in Make.download
Merge branch 'master' of https://github.com/simongog/sdsl-lite into benchmark_wt

Conflicts:
	benchmark/wavelet_trees/Makefile
	benchmark/wavelet_trees/src/gen_bwt.cpp
Added integer testcase, reduced repeats of interval_symbols on inputs with large alphabets
Fixed accuracy in construction time.
Merge pull request #129 from xosh/benchmark_wt

Benchmark wt