Substituted requests package with urllib

[remorses]

Now memory usage is much smaller ( 7 Mb instead of 15 Mb ).

Line #    Mem usage    Increment   Line Contents
================================================
     6     10.5 MiB     10.5 MiB   @profile
     7                             def main():
     8     17.5 MiB      7.0 MiB       import fastjsonschema
     9                             
    10                                 schema = {
    11                                     'properties':
    12                                         {
    13     17.5 MiB      0.0 MiB                   'hey': {}
    14                                         },
    15                                     'required': [
    16     17.5 MiB      0.0 MiB               'hey'
    17                                     ],
    18     17.5 MiB      0.0 MiB           'type': 'object'
    19                                 }
    20                             
    21     17.6 MiB      0.1 MiB       validate = fastjsonschema.compile(schema)
    22                             
    23     17.6 MiB      0.0 MiB       validate({'hey': 'man'})

[horejsek]

Version 2.9 released.