A faster reflection system for Peewee connections

[albireox]

Fixes #30.

Provides an alternative system to reflect models using caching to minimise the number of queries required.

[coveralls]

Pull Request Test Coverage Report for Build 228

• 0 of 105 (0.0%) changed or added relevant lines in 5 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage remained the same at 0.0%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
python/sdssdb/utils/ingest.py	0	1	0.0%
python/sdssdb/peewee/sdss5db/catalogdb.py	0	2	0.0%
python/sdssdb/utils/internals.py	0	29	0.0%
python/sdssdb/connection.py	0	34	0.0%
python/sdssdb/peewee/init.py	0	39	0.0%

Files with Coverage Reduction	New Missed Lines	%
python/sdssdb/peewee/init.py	1	0%

Totals
Change from base Build 227:	0.0%
Covered Lines:	0
Relevant Lines:	5048

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💛 - Coveralls