Fixed Tox sync.
Merge branch 'master' of https://github.com/mannol1/ProjectTox-Core into mannol1-master
Merge branch 'master' of https://github.com/mannol1/ProjectTox-Core into mannol1-master
Replaced tox_wait* functions with tox_do_run_interval().

Build system fixes.
Merge branch 'master' of https://github.com/mannol1/ProjectTox-Core into mannol1-master
Renamed tox_do_run_interval to tox_do_interval.

tox_do_interval now returns a time in ms based on how much action
is going on in net_crypto.
Fixed the undefined reference to pow error
Merge branch 'nurupo-pow-fix'
We gon let it burn burn burn
Merge branch 'mannol1-master'
Fixed typo.

This typo doesn't actually cause any side effects unless you are like
stqism and have a C library that doesn't have mempcpy().
Fixed TOX_MAX_MESSAGE_LENGTH define.

Removed some useless code from toxcore.

Astyled core code with new version of astyle.
tox_test now checks if TOX_MAX_MESSAGE_LENGTH is correctly set.
Increased some timeouts to try to prevent disconnections when
transferring files on wireless networks.
Added instructions on how to pause/resume file transfers.
This might fix the issue that someone reported about tox no longer
cross compiling for windows.
Tweaked file transfers a bit.
Added data packet padding to toxcore.

Data sent as lossless or lossy is now padded with:
((MAX_CRYPTO_DATA_SIZE - data_length) % CRYPTO_MAX_PADDING) bytes
in order to reduce the possibility of length related attacks.

I set CRYPTO_MAX_PADDING to 8 but it can be changed anytime without
breaking network compatibility between tox cores.
Request packets are now sent with send_data_packet_helper().

This means all data packets are now padded the same way.
Doubled minimum transfer rate.

File transfers got stuck because it was too low.