Adds vimpager_ansiesc option to allow ANSI escape codes

Defaults to allowing escape codes if the ":AnsiEsc" command is
available. If ":AnsiEsc" is available, it will be executed.
Update README.md for Ubuntu

Added options required on Ubuntu since it gets installed to /usr/local/bin when you run 'sudo make install' because it fails due to lack of permissions if you don't use sudo.
Support for MSYS2.
Fix temporary paths in both MSYS and MSYS2.

  * $ORIGINAL_TEMP isn't actually exported from /etc/profile in MSYS2,
    switching to $temp.

  * MSYS actually does define $MSYSTEM, so we now rely on the absence of $temp
    for identifying it (hopefully this is cheaper than checking the version with
    `uname -r`).
Added vimcat.1 to 'all' rule in Makefile
Merge pull request #84 from ahamad-s/master

Added vimcat.1 to 'all' rule in Makefile
make tmp code more readable
fix tmp file handling
Merge pull request #86 from rkitover/tmp

fix some issues with tmp files
Merge pull request #83 from renatosilva/vimcat-msys2

Support for MSYS2.
fixes for #83

 * enclose MSYS specific code in a uname -s check
 * correct :endif count
 * add MSYS2 support for vimpager as well
 * fix up copyrights to include contributors
 * add CONTRIBUTORS entry for submitter (renatosilva)
Merge pull request #82 from dragon788/patch-1

Update README.md for Ubuntu
update docs for #82 and other stuff

 * add INSTALL section
 * assume path is /usr/local/bin as per 'sudo make install'
 * update SYNOPSIS to reflect differences in piping versus argument
 * rebuild
update CONTRIBUTORS
Merge pull request #81 from SethMilliken/ansiesc

Adds vimpager_ansiesc option to allow ANSI escape codes
add SethMilliken to CONTRIBUTORS
bundle AnsiEsc and redo logic of #81 (WIP)

We now bundle the improved version of AnsiEsc
(http://www.vim.org/scripts/script.php?script_id=4979) as a uuencoded
tar inside the script which expands at runtime into a prepended temp
directory in runtimepath.

AnsiEsc is only activated if the "conceal" feature is available, it is
not on the default vim on OS X, but is in the Homebrew version of vim.

Also there is no longer an option to turn on AnsiEsc, it gets turned on
automatically if the source file has ANSI codes and the conceal feature
is available.

Document all of this and rebuild docs.

Also move the ~/.bashrc settings into the INSTALL section.

Rebuild docs.

A copy of the above mentioned AnsiEsc has been placed into the ansiesc/
directory inside the project, and it gets automatically installed into
the vimpager script when you run "make".

The uuencoded tar is not gzipped, in case the system does not have
gunzip (e.g. bare Solaris installs.) This makes the script much larger,
but the function is at the end and will not get too much in the way of
development.

TODO:

 * whitespace errors bleed in git diff, this needs fixing in AnsiEsc

 * find a version of uudecode implemented in awk, so as not to rely on
   the system version, which may not be available.
bundle less.vim with our changes

less.vim is now bundled using the mechanism we used for AnsiEsc.

Running 'make' will include it in vimpager, so do that to test your
changes to it.

Some of the tweaks were moved from -c commands to vim into less.vim.

TODO:

 * make our tweaks generic and send patch upstream for less.vim
add sh fallback for uudecode

Add a POSIX sh implementation of uudecode to fall back on if uudecode is
not available, from http://www.weeklywhinge.com/?p=108 .

It is *EXCRUCIATINGLY* slow. We should probably print a warning if
uudecode is not available.
only extract AnsiEsc if needed

Check the correct variable before extracting AnsiEsc via uudecode and
tar, the one that is set if AnsiEsc can be used (conceal feature is
enabled) and the file has ANSI escape codes.