Use own cache filename for each network interface

Template for cache filename is '%s.cache'. '%s' receives network interface name.
If interface is not specified, inadyn uses default cache filename inadyn.cache.

This patch avoids race condition, when two inadyns uses the same cache file.
Merge pull request #16 from taem/cache

Use own cache filename for each network interface
Free resources when restarting daemon
Merge pull request #17 from taem/fixes

Free resources when restarting daemon
Update email and homepage addresses after server crash.
Set INADYN_{IP,HOSTNAME,IFACE} environment variables for external command

External command can use following environment variables: INADYN_IP,
INADYN_HOSTNAME. First environment variable contains new IP address,
second one - host name alias. INADYN_IFACE is available, if --iface
option used.
Merge pull request #18 from taem/env

Set INADYN_{IP,HOSTNAME,IFACE} environment variables for external command
Fix strict-aliasing warnings

Fix from glibc commit 7dc6bd90c56 "Use union to avoid casts in code to
store results of hashsum computations"
Added --test option to force one update and exit. Also fixed a bug where alias hash was improperly parsed for FreeDNS.
Merge pull request #21 from kreed/strict-aliasing

Fix strict-aliasing warnings in md5.c
Merge pull request #22 from pryvkin/master

Fixed FreeDNS problem and added --test option
Merge branch 'master' into debian
Bump standards version to 3.9.4
Add debian branch to Vcs-Git field
Update homepage
Bump debhelper version to 9
Update debian/copyright
Update debian/inadyn.init
Replace /var/run with /run
Drop build flags detection