Relicense to LGPL 2.1 and thus update license and headers

This relicensing was requested and approved by all authors by E-Mail.
Update README with proper text description
Update description in pkg-config file
Add support for iPhone 5S, iPhone 5C and Apple TV 3G Rev A
Silence compiler warnings by returning proper error with irecv_control_transfer
irecovery: Output basic device information after connecting
Remove demo scripts from sources
Move irecovery to new tools directory
Remove rather obsolete irecv_hexdump() helper
Bump version to 0.2.0
Revert changes to return errors when sending commands, getenv or getret

This fixes software which did not expect to receive an error after sending
specific commands. Sending "go" for instance returned a connection reset
error which was interpreted as "could not send command" while this behavior
is completely correct. This also fixes idevicerestore's "Unable to send iBEC"
problems.
Remove obsolete "in-tree" copy of libusb-1.0
Remove unmaintained TODO and Makefile.shared files
Update .gitignore file
Use foreign automake rules to prevent mandatory files that we don't use
Bump soname
Clean up and update build system files
Fix header comment syntax
Convert spaces to tabs were needed
Only enable libusb debugging output on verbose level 2 and higher