CTextBox: fix return value of getMaxLineWidth()

m_nMaxLineWidth was never used
Rework display LOCALE_SERVICEMENU_RELOAD_HINT message

- remove the very short visible message in channelsInit()
- remove global reloadhintBox

Signed-off-by: Thilo Graf <dbt@novatux.de>
configure: add libsigc++ support
CComponents: add new header file cc_signals.h with some basic members
CComponentsSignals: add signal OnError
CComponentsWindow: add missing comment for allignment options
CProgressWindow: optimize fontsize handling

- minimal size is now 14 instead 20, changed scale settings now should
  be noticed earlier
- font type is now bold
- arrangement of progressbars adapted
nhttpd: let sendfile() support files >= 2GB
gui/filebrowser: don't show progressbar unless directories were added
Revert "nhttpd: let sendfile() support files >= 2GB"

This reverts commit 9842afecad8dfb91dfd7221aedbeaf5379a89534.
nttpd: allow sendfile() to cope with files >= 2GB; introduce range support

(This re-applies most of the patches I've reverted about two hours ago.)
nhttpd: fix range handling
nhttpd: extend sendfile mime types (untested)
- nhttp: some minor code optimizations
- movieplayer: ask before stop temporary timeshift
- nhttp: enable threading

This is ported from neutrino-mp and contains code by martii and seife
from following commits:
20d3031b8bb47b5af79bf10c385e3564fe5c26dc
93d01c1987726c6ab344f69f799df03d5af8fe7a
363633dc1b9a508e244c7e1e51f6c1bbe699961c
c3e1310a2f727e26ce11669e3aeae78305f87049
- yWeb: add boxinfo extention source
- yWeb: add filemanager extention source
- yWeb: add hddtools extention source
- yWeb: remove some links to yjogol.com; site is down

TODO: Y_Tools_Check_Install.yhtm