Misc07 cleanup multipletesting and proportions

first part: some cleanup of multipletesting, 
    see also http://jpktd.blogspot.ca/2013/04/multiple-testing-p-value-corrections-in.html
    closes #763
    closes #764
    closes #766

Note: includes several backwards incompatible renames in weightstats

second part: statistical test for proportions and normal based tests

some functions still miss unit tests :

  - (almost full coverage in weightstats (97%) and proportions (92%), one method and a few lines left untested)
  - not all features tested, latest statistical tests don't have shape/2d tests

currently all written as individual functions :

   - maybe add a class to collect methods, add plotting ?
   - and more results classes
   - the allpairs tests return a results instance, all others just numbers

some functions are still missing (ztest_prop, with more options than generic ztest), mostly done, I think

adding ztest and ztost to weightstats is incomplete (not attached as methods) DONE

ddof again: 

   - I need them for proportion and correlation for the z-based tests see b46ed52
   - currently I added them to the standalone functions but not the methods