[layer23] Disabled may debugging in cell selection process

This way the syncing and cell selection can be reviewed much better.
[layer23] Disabled the scanning of maximum cells per band

This way all frequencies are scanned, in case they meat the minimum
receive level.
[layer23] Added a workarround to ignore the first (invalid) PM result
[layer23] Disabled display of SYSINFO message at message handlers

This way the SYSINFO is logged once and not three times.
gsm0480: Add USSD format functions to libosmocore

These routines come from OpenBSC, the msgb_wrap_* functions
belong to Mike Haben, the rest is mine. The msgb allocation
is compatible to the GSM48 allocation in OpenBSC.
[layer23] Using loglevel to disable heavy debugging on cell selection
[layer23] Remove obsolete function from header file
[layer23] Minimum RX-level is now a configuratio option

The default (if config not yet created/updated), is still taken from
settings.c.
[layer23] Notify user when config change requires restart to take effect
sercomm.c: Avoid unused variable compiler warning

For the host build the local_irq_save/_restore is a NOOP
and the compiler warns about the unused flags variable. Cast
it to void to avoid compiler warning.
osmocon.c: Use C99 inttypes instead of u_intX_t.
osmocom.c: rc is not assigned and contains garbage, return 0.
osmoload.c: Cast to uint8_t from char* to fix a compiler warning
sim.c: Fix NULL pointer dereference found by clang.
msic: Include osmocom/util.h for the hexdump definition
gsm48_rr.c: Move the access below the parsing (found by clang
misc: Fix the name of the header file for the hexdump...
[layer23] Rework of "support"-features, features can be disabled now

Supported features of hardware (support.c) can be disabled by config.
This way the full featured mobile can be downgraded to indicate less
features to the network, like disabling speech support or crypto support.
[layer23] Fixed emergency call setup
[layer23] Fixed ACCH reception of TCH channels

Without it, the indicated TA and power never get received by layer23.
This may cause a release duing TCH on certain networks. Also it
is required to apply timing advance and transmit power during movement.