BUG: fix df repr troubles GH3337
ENH: add internal get_default_val() function to core.config
ENH: add helper for detecting any IPython zmq frontend, make in_qtconsole robuster
BUG: Always Ignore auto-detect terminal size for qtc/+ipnb

this is ignored anyway unless the user sets width/height to 0,
but even then, size detection only works for proper terminals.
DOC: Add comments, tweak option descriptions.
CLN: convert test utilizing disp.line_width to disp.width
ENH: Adjust height/width/max_rows defaults to match informal survey results
TST: adjust tests to accommodate new defaults for display options
TST: fix test_repr_non_interactive passing by accident
BUG: for numerical option, sentry should be another Type, not 0
ENH: optimize _repr_fits_horizontal_, to_string only on slice of interest
BUG: rework get_console_size to handle cases properly
ENH: fix df.repr() for scripts (keep GH1611 away), accept None for max_cols/rows
ENH: let display.notebook_repr_html control HTML repr in qtconsole again.

Where it belongs.

https://github.com/pydata/pandas/issues/2275#issuecomment-10908413

It'll probably never happen that QTconsole will report it's width, let alone
in characters (variable-width font and all). Best let the user decide.
ENH: default dimensions for ip zmq frontends derive from disp.height/width defaults
BUG: fix validators for config options
DOC: RELEASE.rst mention new options disp.height/width and deprecated line_width
TST: add test for config.is_one_of_factory
BUG: config.is_one_of_factory is broken
Merge branch 'repr_fixes'

* repr_fixes:
  BUG: config.is_one_of_factory is broken
  TST: add test for config.is_one_of_factory
  DOC: RELEASE.rst mention new options disp.height/width and deprecated line_width
  BUG: fix validators for config options
  ENH: default dimensions for ip zmq frontends derive from disp.height/width defaults
  ENH: let display.notebook_repr_html control HTML repr in qtconsole again.
  ENH: fix df.repr() for scripts (keep GH1611 away), accept None for max_cols/rows
  BUG: rework get_console_size to handle cases properly
  ENH: optimize _repr_fits_horizontal_, to_string only on slice of interest
  BUG: for numerical option, sentry should be another Type, not 0
  TST: fix test_repr_non_interactive passing by accident
  TST: adjust tests to accommodate new defaults for display options
  ENH: Adjust height/width/max_rows defaults to match informal survey results
  CLN: convert test utilizing disp.line_width to disp.width
  DOC: Add comments, tweak option descriptions.
  BUG: Always Ignore auto-detect terminal size for qtc/+ipnb
  ENH: add helper for detecting any IPython zmq frontend, make in_qtconsole robuster
  ENH: add internal get_default_val() function to core.config
  BUG: fix df repr troubles GH3337