build: no need to quote the paths in CMake, it will do it automatically
build: only manipulate out if getting the timestamp was successful

This fixes an issue seen in #1548, though the real problem is something
different.
doc: Misc. improvements to nvim-related docs

- Improved wording in a few places for clarity
- Various capitalization/grammar fixes
- Change references to Neovim as 'editor' to 'Nvim'
- Be consistent regarding utilization of vim's documentation features,
  e.g. unnamedclip -> |unnamedclip|
- Reflowed all changed paragraphs accordingly

- Add spaces before parentheses
- Remove trailing whitespace
- Standardize single spaces after periods. Vim's docs use two for the
  most part, but Nvim's use one mainly, so just follow Nvim's conventions
Merge pull request #1624 from Pyrohh/doc-fixes

doc: Misc. improvements to nvim-related docs
deps: Update lua client
clipboard: support separate '+' and '*' clipboards
clipboard: handle linewise/charwise selections correctly
clipboard: clean up unnamedclip logic
options: change "unnamedclip" back to "clipboard=unnamed/unnamedplus"

This allows to configure which of '*' and '+' should be used for
the unnamed clipboard, and is consistent with vim.
clipboard: better error messages when provider not available
clipboard: add functional test
clipboard: fix `let @+ = ...` and add test
eval_has_provider: search autoload scripts same order as call_func
Merge pull request #1599 from jszakmeister/gitrev-fixes

Some simple fixes to GetGitRevisionDescription.cmake.
docs: remove unnamedclip option
Merge pull request #1182 from bfredl/clipboard

clipboard: support separate +/* clipboards, linewise copy/paste and add tests
msgpack-rpc: Allow registration of handlers by other modules
ui: Add abstract_ui termcap and split UI layer

This is how Nvim behaves when the "abstract_ui" termcap is activated:

- No data is written/read to stdout/stdin by default.
- Instead of sending data to stdout, ui_write will parse the termcap codes
  and invoke dispatch functions in the ui.c module.
- The dispatch functions will forward the calls to all attached UI
  instances(each UI instance is an implementation of the UI layer and is
  registered with ui_attach).
- Like with the "builtin_gui" termcap, "abstract_ui" does not contain any key
  sequences. Instead, vim key strings(<cr>, <esc>, etc) are parsed directly by
  input_enqueue and the translated strings are pushed to the input buffer.

With this new input model, its not possible to send mouse events yet. Thats
because mouse sequence parsing happens in term.c/check_termcodes which must
return early when "abstract_ui" is activated.
syntax: Use RGB/GUI attribute information for "abstract_ui"

Instead of using classic cterm color numbers and attributes, treat "abstract_ui"
as a GUI: Pass rgb color numbers and gui attributes when the "highlight_set" UI
method is called. The terminal UI will have to translate RGB color information
to an appropriate color number, and the "term"/"cterm" :highlight keys will
eventually be deprecated.
msgpack-rpc: Add remote_ui module

The remote_ui module is an implementation of the UI layer, and it attaches UI
instances that redirect redraw notifications to connected clients.