accept a list of documents + add related options

* treat all the remaining positional arguments as file names,
  instead of just one (can use shell wildcards)
* show all the documents following the order of the file names
* add -j option to run in an infinite loop and keep showing all
  the documents
* add -g option to specify the pause duration before showing the
  next document
epview.c - allow SIGINT to cleanly exit the application

Add a signal handler to catch SIGINT and exit the application
cleanly. Previously we were just letting the OS tidy up.

Conflicts:

	epview.c

Signed-off-by: Guillaume Tucker <guillaume.tucker@plasticlogic.com>
improve SIGINT handling

* add Stopping... log message when SIGINT received
* test g_run flag inside document loop before and after sleep to
  avoid waiting until the end of the loop or the sleep duration
  before stopping
add setver.sh script to set the application version string

This script takes care of updating the application version string
in epview.c and adds it to the git index for automatic version
update when running release script.
ChangeLog v1.7 -> v1.8