[hotfix] don't allow no value fields in the search fields

Import six.moves.urllib.parse.urlencode instead of urllib.urlencode

Import six.StringIO instead of StringIO.StringIO

Use PyPDF2 instead of pyPdf

Replace Py2 raise syntax with Py 3

* Don't expand mailto urls

* Add test case

Make sure that max_length[0][0] is comparable with new_length

Replaced long with six.integer_types

Convert method name to string instead of encoding

Explicitly convert dict.values() to list

Replaced all instances of basestring with six.string_types

Encode string before passing to hashlib.sha224

Use abslute imports in frappe/__init__.py

Use string.ascii_letters instead of string.letters

Use absolute import to import frappe.utils.background_jobs

Encode 'site' before passing to hashlib.sha1

Convert dict.keys() to list

Hide Toolbar Buttons Until Drop Down Is Populated

Fix date cached between forms