added intent-filter tricks from vplayer to get more files sent to gpgcli (refs #1455 refs #1454)

It seems that you need to have a bunch of different intent-filters in order
to actually receive the files in all the relevant cases.  But there are
still problem spots, for example OI File Manager does not find any app for
.gpg files, even tho gpgcli, APG, and OpenPGP Keychain all are setup to
receive them.
include file encrypted to the test key as test fodder
add PGP's .pkr as a supported file type (refs #1455 refs #1454)

.pkr is the Public KeyRing binary format from PGP
force the gpg lib/ paths into the LD_LIBRARY_PATH, don't expect them to be set

getenv(LD_LIBRARY_PATH) does not always give us the two paths that gpgme
and the command line tools need in order to find their libs.
remove unused file: res/menu/activity_pinentry.xml
rename XML files for an Activity's main menu after the Activity
add "Decrypt File" dialog to the debug suite
move run-tests.sh and pinentry-tests/ into assets, they are not external

external/ should be for submodules and the build system directly related
to the submodules.  pinentry-tests/ and run-tests.sh are installed into
assets/ but are not submodules nor part of their build system.  Therefore,
I moved them to assets/, and they no longer need to be installed.