Fix issue when seconds is greater than two digits.

Also only use one query rather than a loop.
Report properly when value is undefined (slave error).
Made Munin plugin to graph signal levels from a Cisco EPC3010 cable modem
Fixed some typo in text
Changed to a more secure way of handling tempfiles
Moved all Raspberry Pi plugins to a common raspberry-pi directory. Removed absolute path in raspi_temp to make the plugin work on Pidora.
Simplified parsing of the html table. Everything is done with awk. Got rid of cat and grep
Changed how tempory filename is created and handled. Now follows example in mktemp documentation.
p/cisco-epc3010_: fix tmpfile handling