Merge pull request #3741 from cpcloud/read-html

TST/BUG: fix bs4 tests that were getting erroneously run when lxml is installed but not bs4
DOC: update io.rst for PyTables 3.0.0 compat
DOC: fix typo in core.series.__new__ docstring
DOC: document the various pitfalls of reading html

DOC: change formatting

DOC: more formatting

DOC: add bold substitutions

DOC: fill out bold links and rephrase

DOC: fill out link to gotchas

DOC: add gigantic install.rst warning

DOC: move version note about html5lib to first mention of it

DOC: add same to readme and add boto to install.rst

DOC: add anaconda note

DOC: add note about debian based system installation

DOC: add correct lexer for pygments formatting of code snippets

DOC: move boto up
Merge pull request #3751 from cpcloud/read-html-bs4-install-docs

DOC: document bs4/lxml/html5lib issues
DOC: minor issue with the description of the names attribute of multiindexes
BUG: (GH3611) revisited; read_excel not passing thru options to ExcelFile.parse

API: add string and numeric versions of na_values when parsing
Merge pull request #3758 from jreback/parse_na

BUG: (GH3611) revisited; read_excel not passing thru options to ExcelFile.parse