added make target to build single file script

as it is quite unusual to have monitoring plugins consisting of multiple files,
it is handy to build the plugin for production by a simple make target. The Makefile
just concatenates all files and removes the use lib and use modules.
replace imports and requires too

Signed-off-by: Sven Nierlein <sven@nierlein.de>
don't wait for stdin unless attached to a tty

otherwise ex.: "check_vmware_esx | less" will fail to output and exit.

Signed-off-by: Sven Nierlein <sven@nierlein.de>
New version 0.9.4 - Minor bugfixes See HISTORY
modified:   HISTORY
modified:   README
modified:   check_vmware_esx.pl
modified:   modules/host_net_info.pm
modified:   modules/host_runtime_info.pm