Merge pull request #399 from weese/hotfix/fiona-ambiguous-pow

[FIX] fixed ambiguous pow() in fiona (master)
[FIX] fixed fiona issues and mingw warnings
Merge branch 'develop' into hotfix/fiona-vs8-devel

Conflicts:
	core/include/seqan/bam_io/bam_sam_conversion.h
[FIX] replaced problematic isblank by comparison
Merge pull request #404 from weese/hotfix/fiona-vs8-devel

[FIX] fixed fiona issues and mingw warnings (devel)