TST: Deprecation -> FutureWarning + catch in tests
BUG/TST: fix get_schema + add tests

- adapt signature of get_schema to what it was before (for backwards compatibility), possibility to call function without connection object
- fix get_schema for sqlalchemy mode
- add tests
SQL: revert deprecated tquery/uquery to 0.13 version

As tquery and uquery are deprecated, it is not needed to adapt them to the new sqlalchemy interface + the adapted version changed the signature slightly so it was not fully backwards compatible.
Therefore: put back the old code and removed new implementatation in the classes.
Consequence: the functions are not available for the new sqlalchemy engines, but as they are deprecated this is not needed.
BUG: fix handling of color argument for variety of plotting functions

parallel_coordinates
- fix reordering of class column (from set) causing possible color/class
  mismatch
- deprecated use of argument colors in favor of color
radviz
- fix reordering of class column (from set) causing possible color/class
  mismatch
- added explicit color keyword argument (avoids multiple values 'color' being
  passed to plotting method)
andrews_curves
- added explicit color keyword argument (avoids multiple values 'color' being
  passed to plotting method)
TST: add tests for deprecation warnings from plotting functions

parallel_coordinates/andrews_curves
- added deprecate_kwarg decorator for using frame argument instead of data
- added tests to check that FutureWarning is raised properly
DOC: Reorganize visualization.rst

- add matplotlib to intersphinx
- put random seeds in supress and note
- use versionadded in more places
- link to api on more methods
- title case titles
- reorganize hierarchy

The new hierarchy is

- Basic Plotting (line plots on Frame and Series)
- Other Plots (bar, scatter, etc.)
- Plot formatting

DOC: add ecosystem note to top of visualization.rst

DOC: use cubehelix, not jet

fix line lengths on headers

reorg hierarchy to basic, other, and styling

Change matplotlib url
Merge pull request #7027 from TomAugspurger/visualization-rewrite

DOC: Visualization reorganization
DOC: Add parameter to docstring
ENH: cythonize groupby count
VB: add a vbench for groupby count
BUG: numeric_only must be False for count
CLN: EAFP for count
DOC: add release and v0.14.0.txt notes
Small typo
Merge pull request #7046 from jseabold/docs-fix

DOC: Add parameter to docstring
Merge pull request #7047 from jsexauer/patch-1

DOC: Small typo
Merge pull request #7016 from cpcloud/groupby-count-cython

ENH: cythonize groupby.count
Merge pull request #6956 from anomrake/plotting

BUG: fix handling of color argument for variety of plotting functions
SQL: put old tests back + some fixes to get them running

- removed meta keyword from has_table (was not used)
- added check for if_exists
- added table_exists back as alias for has_table
- added frame_query back as alias for read_sql (and deprecated it)
- changed way to delegate read_sql/table without using has_table for backwards compatibility (because this gave an error when uqing a mysql connection but not specifying the flavor)

Things that I had to change to the tests to get them running:
- changed MySQLdb to pymysql
- changed `sqlite3.OperationalError` to `pd.io.sql.DatabaseError` (in `test_tquery` and `test_uquery`)
- test_write_row_by_row are skipped for now (they depend on the issue of `execute` being able to handle cursor objects).
- in `test_execute` with pymysql converted the row values to python types (with numpy's `tolist()`), as pymysql errored on the numpy types.
DOC: release notes / v0.14.0 edits