Turn off filters compilation.

Filters needs complete rework. Now it incompatible with latest ffmpeg.
Merge branch 'master' of github.com:h4tr3d/avcpp
Initial API Rework
API2 rework

- removed 'using namespace' in headers
- complete demux/decoding pipeline
- demux/decode example
Change av::Direction type

Change av::Direction type from 'enum' to 'class enum'
API2 Rework

Complete video decoding/encoding
Complete demixing/muxing
API2 Rework: sws rescaler

Adopt VideoRescaler to work with VideoFrame2
API2 Rework: new method isFlags() in Format<T> class

Method checks that provided flags is set return true on success, false
otherwise.
API2 Rework: fix possible corrupt in CodecContext::isValid()

Check parent stream for valid first, after that check m_raw and m_raw-
still non null, but is free'd, so access to m_raw->codec is invalid.
API2 Rework: Ignore SIGPIPE by default.

Set SIGPIPE signal ignoring in av::init() by default.
API2 Rework: fix/new samples

Fix: api2-samples/av-decode-encode-video.cpp
New: api2-samples/av-scale-video.cpp

Note, av-scale-video.cpp same to av-decode-encode-video.cpp but contain
scaler. Scaler setted automaticaly on demaind.
API2 Rework: fix const-correctness in VideoRescaler

Src argument of VideoRescaler::rescale() must be const ref.
API2 Rework: check Frame<T> for valid with isVaid()

Method returns true is !isNull() and data[0] is not null e.g. image
filled with data.
API2 Rework: fix VideoFrame2 coping
API2 Rework: correct clean up codec contexts

Correct clean up codec contexts on destroing unopended FormatContext.
API2 Rework: added ability to reset codec defaults on setting codec
API2 Rework: minor & cosmetic changes on av-scale-video sample
Merge branch 'api-rework' of github.com:h4tr3d/avcpp into api-rework