stop sourcing vimrc/gvimrc twice

Sourcing vimrc/gvimrc twice was causing problems for some people:

https://github.com/rkitover/vimpager/pull/32

however this was done in 7b92857 because the "syntax on" statement in
less.vim resets highlights.

The requestor suggested a more elegant solution to that issue, which
also fixes his, that is to use --cmd 'runtime! macros/less.vim' instead
of -c to source less.vim. This seems to not cause any problems, and we
can remove the re-sourcing of the rc files.
release 1.6.9
try fix for OpenBSD ps (GitHub Issue #33)

OpenBSD ps uses -o command instead of -o comm format for the ps command,
according to the man page and the submitter. I haven't tried this fix
yet, going to install an OpenBSD VirtualBox image to try it out.
add mapping for q (GitHub Issue #34)

As of a8f81d6 plugins could override less.vim's mapping of q since the
sourcing of less.vim was moved to a --cmd.

Add a noremap for q to -c (which is after .vimrc/.gvimrc and plugins are
loaded.)
release 1.7.0
add OpenBSD to compatible OS list
Reorder q -> :q<CR> to fix up/down
Merge pull request #35 from lickel/up-down-fix

Reorder q -> :q<CR> to fix up/down
add lickel to CONTRIBUTORS
release 1.7.1
Pass through if content is short compared to terminal size.

* BSD-licensed calculation algorithm from [p][1] by Akinori MUSHA.
* Function `col_b' renamed to `fitler'.
* Moved terminal size detection code so that function `filter' can use it.
* ANSI-escape-code-removing sed command moved to `filter'.
* Global variable `$no_pass_thru' introduced.
* Set `$no_pass_thru` if we can't detect terminal size.

Note:
Outputting to STDERR in `filter' is not an elegant solution, but
`filter' has to be able to run in a sub-shell for `.gz' and `.Z' files,
which means `filter' cannot alter the outside shell environment.

[1]: https://github.com/knu/p
major refactor and experimental vimcat utility

Fix a bug in de3d11c where filename arguments would cause vimpager to
just hang.

Also make de3d11c turn on only if the vimpager_passthrough option is
set. The rationale for this is we cannot yet do highlighting for text
dumped to the terminal. The vimcat utility (based on _v by Magnus
Woldrich: https://github.com/trapd00r/utils/blob/master/_v) almost does
this, but has some highlighting bugs on OSX.

When the vimcat utility is functional, we'll have to turn vimpager into
a dist and install both of them, with vimpager using vimcat, but that's
when it works.

Also turn off the passthrough option if the shell doesn't have
arithmetic expansion, as that code relies on it.

Major refactor of option reading, vimrc/gvimrc finding, and tempdir
handling for more portability.

Makes the code generally less ugly.
regen docs
release 1.7.2
fix usage with no .vimrc (Github Issue #38)

Now that every vim/gvim invocation uses -u to point to the vimrc, which
is read from vim's $MYVIMRC variable, there is a problem if there is no
user vimrc ($MYVIMRC is empty) and -u reads the next argument as the
vimrc, completely breaking vimpager.

Detect this situation and set vimrc to 'NORC'.
release 1.7.3
improve $VIM detection for Win32

Read $VIM in the configuration reading block instead of the $MYVIMRC
reading block, because the user may have a .vimpagerrc and still need
$VIM to detect the _gvimrc on Win32 (cygwin or msys.)
release 1.7.4
Add global configuration file.
Avoid old-style backquote.