Satsearch "limit" keyword bugs with E84 earthsearch endpoint

[scottyhq]

Setting a limit keyword arg has unexpected results:

import satsearch
URL='https://earth-search.aws.element84.com/v0'
results = satsearch.Search.search(url=URL,
                                  collections=['sentinel-s2-l2a-cogs'],
                                  bbox=[-54, 67.65, -50, 69.37],
                                  datetime='2019-08-15/2020-08-15',
                                  limit=200,
                                 )
print(f'{len(results.items())} S2 Items')

There are more items found (2158) than the limit (200) provided.
500 S2 Items

( I expect to have 200 items returned)

2. changing limit to 700 in the above codeblock surprising leads to:

There are more items found (2158) than the limit (700) provided.
1000 S2 Items

3. increasing limit to a value greater than the total items found results in a internal server error:

---------------------------------------------------------------------------
SatSearchError                            Traceback (most recent call last)
<ipython-input-4-6c0f70cd4c07> in <module>
      7                                   limit=2500,
      8                                  )
----> 9 print(f'{len(results.items())} S2 Items')

~/miniconda3/envs/intake-stac-gui/lib/python3.7/site-packages/satsearch/search.py in items(self, limit, page_limit, headers)
     88     def items(self, limit=10000, page_limit=500, headers=None):
     89         """ Return all of the Items and Collections for this search """
---> 90         found = self.found(headers=headers)
     91         limit = self.limit or limit
     92         if found > limit:

~/miniconda3/envs/intake-stac-gui/lib/python3.7/site-packages/satsearch/search.py in found(self, headers)
     60         url = urljoin(self.url, 'search')
     61 
---> 62         results = self.query(url=url, headers=headers, **kwargs)
     63         # TODO - check for status_code
     64         logger.debug(f"Found: {json.dumps(results)}")

~/miniconda3/envs/intake-stac-gui/lib/python3.7/site-packages/satsearch/search.py in query(self, url, headers, **kwargs)
     78         # API error
     79         if response.status_code != 200:
---> 80             raise SatSearchError(response.text)
     81         return response.json()
     82 

SatSearchError: {"message": "Internal server error"}

This PR seems related #107 (Hi @acannistra!)