BUG: fix CategoricalBlock unpickling

TST: add categorical frame and series to generate_legacy_pickles

TST: generate legacy pickle including frames/series with categoricals
for 0.15.0

COMPAT: ensure pre-0.15.0 pickles of Categorical are read

TST: move assert_categorical_equal to tm.TestCase
Merge pull request #8519 from immerrr/fix-categoricalblock-pickling

BUG: fix CategoricalBlock pickling
Add xray to ecosystem docs

Fixes #8516
Merge pull request #8534 from shoyer/add-xray-to-ecosystem-docs

Add xray to ecosystem docs
DOC: Add 29+ in-line examples, change headings & intro to cookbook GH6918
Merge pull request #8288 from jnmclarty/cookbook_inline_examples

Cookbook Inline Examples 2014Q3
BUG: Dont add None to plot legend.
Merge pull request #8536 from TomAugspurger/plot-label-none

BUG: Dont add None to plot legend.
PERF: Performance improvement for MultiIndexes with a DatetimeIndex level
DOC: Clean Cookbook Issues: Tabs, expanded_apply, axis aliasing, etc.
Merge pull request #8535 from jnmclarty/cookbook_inline_examples

DOC: Clean up Sphinx Issues, fix tabs, in Cookbook
Merge pull request #8544 from mtkni/master

PERF: Performance improvement for MultiIndexes with a DatetimeIndex levels
DOC: v0.15.0 corrections
DOC: Update ecosystem.rst: Add IDE, IPython, qgrid, Spyder, API, quandl, Out-of-core, Blaze

DOC: Update ecosystem.rst: Add IDE, IPython, API
DOC: Update ecosystem.rst: Add GUI > Spyder
DOC: Update ecosystem.rst: GUI -> IDE, IPython > qgrid, API
DOC: Update ecosystem.rst: -> IDEs
DOC: Update ecosystem.rst: depluralize
DOC: Update ecosystem.rst: Add IPython [Notebook] description; alphabetize
DOC: Update ecosystem.rst: add Blaze, alphabetize
Merge pull request #8507 from westurner/patch-3

DOC: Update ecosystem.rst: Add IDE, IPython, qgrid, Spyder, API, quandl, Out-of-core, Blaze