Page size validaton, api search form tests

[philtgun]

• Added tests to validate apiv2 search form cleaning
• Fixed ValueError: invalid literal for int() with base 10: 'test' #1095 related to page_size field
• Fixed bug where normalize field was not being parsed correctly

[ffont]

Thanks for this patch @philtgun, all the code looks really good and comprehensive tests have been added. Maybe tests could be a bit more documented but this is minor issue as the tests are rather simple. Great work!