Add Gentoo installation in README

2650689d introduced a bug:
If we are using a template, GNU mktemp will use PWD instead of $TMPDIR

Use printf, not echo -n to print messages without newline

OS X echo does not understand -n and prints it literally

README.md: Use GFM tables for Usage

Table syntax in GFM?  Oh, yes: 
<https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet#tables>

This reverts commit 794f0aac.

Conflicts:
	vcsh

Turns out the shell implementation didn't account for trailing
slashes. While, arguably, a proper interactive shell should eat
them before execution anyway, this can also be called in script
context.

This means that

    vcsh clone foo/

made it fail and even after commit 7e33e38a

    vcsh clone foo//

would have failed.

Revert to safe and time-proven default: Standalone `basename`.

For further information, see:

https://github.com/RichiH/vcsh/pull/92

If the repository path given to 'vcsh clone' contains a trailing slash,
the resulting cloned directory will be '.git' and vcsh will not
recognize the cloned repository by name. This change ensures that a
trailing slash will be stripped and the repository name will be
populated.

The previous faulty behavior is due to the custom implementation of the
basename command first introduced in 794f0aac.

Removed newline escape sequence that was not properly being obeyed anyway, was printing to the console as is. Not needed because the echo being used already terminates with a newline.

Conflicts:
	Makefile

updated docs to leave out run so it will be consistent

Make Makefile more configurable (doc and zsh dirs)

Some distributions expect the documentation in /usr/share/doc/name, and
others in /usr/share/doc/name-version. The zsh directory for completion
is also configurable due to differences between distributions.

On Macports one need to run ronn-1.9 instead of ronn. Therefore
make ronn tool configurable. one can now run

make RONN=ronn-1.9

to execute ronn-1.9 instead of the default ronn.

Signed-off-by: Gregor Jasny <gjasny@googlemail.com>