Added --noinput option to disable confirmation
Improved NdaModel class finder

* classes can be loaded from different modules
* path to global "ndamodels" can be specified in NDATOR_GLOBAL_MODULE setting
* with NDATOR_SEARCH_IN_APPS option enabled every appname.ndamodels is looked through
fixed english grammar in messages
Version increment
fixed IntegerNda invalid behaviour when min_value == 0
PEP8 code style
Merge pull request #1 from andreiko/master

A few improvements