remove some needless comments
showhours() cleanup
reduce use of global variables in image output
add -nl / --nolegend option to image output for hiding the rx/tx legend
image output cleanup
add legend to hourly ouput image
man page syntax cleanup
new vnstati options: --altdate for using alternative date and time text locations outside header section, --headertext for using custom text in image header section instead of interface name / nick
add option for center alignment
Merge remote-tracking branch 'upstream/master'