Fix conditionals with missing when blocks or missing options

[bernt-matthias]

For conditionals each option should have a corresponding when block and vice versa. The former case should be less critical but also easier to fix:

Here is the list of tools that currently suffer from this (please put your name / link to the PR next to the tool if you are working on this):

• tools/barcode_splitter/barcode_splitter.xml
  • Conditional [nameinterface] no block found for select option 'forward'
  • Conditional [nameinterface] no block found for select option 'reverse'
  • Conditional [nameinterface] no block found for select option 'forwardindex'
  • Conditional [nameinterface] no block found for select option 'reverseindex'
• tools/gecko/gecko.xml
  • Conditional [options] no block found for select option 'noalignments'
  • Conditional [options] no block found for select option 'alignments'
• tools/moabs/moabs.xml
  • Conditional [bsmap_mismatch] no block found for select option '0'
  • Conditional [doComp] no block found for select option '1'

And here are the potentially more difficult cases:

• tools/qiime/qiime_core/pick_otus.xml
  • Conditional [method] no found for when block 'mothur'
  • Conditional [method] no found for when block 'blast'
  • Conditional [method] no found for when block 'sumaclust'
  • Conditional [method] no found for when block 'cdhit'
• tools/qiime/qiime_core/assign_taxonomy.xml
  • Conditional [methodcond] no found for when block 'rdp'
  • Conditional [methodcond] no found for when block 'rtax'
• tools/scanpy/plot.xml
  • Conditional [method] no found for when block 'pl.rank_genes_groups_violin'