uhd:  include gnuradio paths for swig build first

This fixes a potential issue where swig sees old installed headers,
where it should be seeing in-tree headers.
filter: removing '.version' lines in ASM code for compat with CLANG.
core: Adding a file sink block that stores metadata with file.

Current working version only has a single header at the top of the file.

Must update to add metadata fields when changes occur. Also adding extra_header structure to store extram, users-specified info.
core: adding Python files to easily parse header info of a file.

Also a utility script that you pass a filename to and it prints out the meta data.
core: adding GRC file for file metadata sink
core: Update file_meta_sink to inject headers into data stream.

When a tag with updated metadata information is received, close out the previous header (by setting the segment size) and create a new header with the new data. Specifically for sample rate and time stamps. Will be useful for extra_dict when implemented.
core: adding ability to handle extra data in headers.
core: adding a max segment size to metadata files.

Automatically generates a new header after the MSS is reached.

Also adds a metadata format version number (starting at 0).
core: updated metadata structure to use relative header info.

Now the start tag info in the header is relative to the begining of the header (so, basically, the size of the header + extras).
core: Update metadata file sink to better handle tags in the right spot.
core: metadata file parser updated for more sig figs on display.
core: Use sample and relative rate to update header based on num samples.

When the max segment size is reached, we insert a new header. This updates the timestamp on that header based on the number of samples seen.
core: update to metadata files to grow the extras dictionary when any tag is seen.
core: metadata file sink can set detached header.

This breaks away from subclassing gr_file_sink_base since we have to keep track of two files.
qtgui: adds parameter in qtgui sink's GRC block to set the update rate.
core: better error handling on file source/sink.

This addresses ticket #448.
core: Patch to file source to allow opening of new files while running.

Addresses issues #352.
blocks: apply changes to file source in core to one in gr-blocks.
build: removing core_swig from GR_SWIG_TARGET_DEPS. Seems to have been the cause of the parallel build woes.
Merge branch 'maint'