Updated BEDOPS recipe to support v2.4.3

* Compilation improvements

  - Shane Neph put in a great deal of work to enable parallel builds (e.g., `make -j N` to build various targets in parallel). Depending on the end user’s environment, this can speed up compilation time by a factor of 2, 4 or more.

* Fixed numerous compilation warnings of debug builds of starch toolkit under RHEL6/GCC and OS X 10.10.1/LLVM.

* New `bedops` features

  - Added `--chop` and `--stagger` options to “melt” inputs into contiguous or staggered disjoint regions of equivalent size.

  - For less confusion, arguments for `--element-of`, `--chop` and other `bedops` operations that take numerical modifiers no longer require a leading hyphen character. For instance, `--element-of 1` is now equivalent to the former usage of `--element-of -1`.

* New `bedmap` features

  - The `--sweep-all` option reads through the entire map file without early termination and can help deal with `SIGPIPE` errors. It adds to execution time, but the penalty is not as severe as with the use of `--ec`. Using `--ec` alone will enable error checking, but will now no longer read through the entire map file. The `--ec` option can be used in conjunction with `--sweep-all`, with the associated time penalties. (Another method for dealing with this issue is to override how `SIGPIPE` errors are caught by the interpreter (`bash`, Python, etc.) and retrapping them or ignoring them. However, it may not a good idea to do this as other situations may arise in production pipelines where it is ideal to trap and handle all I/O errors in a default manner.)

  - New `--echo-ref-size` and `--echo-ref-name` operations report genomic length of reference element, and rename the reference element in `chrom:start-end` format (useful for labeling rows for input for `matrix2png` or `R` or other applications).

* `bedextract`

  - Fixed upper bound bug that would cause incorrect output in some cases

* Conversion scripts

  - Brand new C99 binary called `convert2bed`, which wrapper scripts (`bam2bed`, etc.) now call. No more Python version dependencies, and the C-based rewrite offers massive performance improvements over old Python-based scripts.

  - Added parallel `bam2starch` script, which parallelizes creation of Starch archive from very large BAM files in SGE environments.

  - Added bug fix for missing code in `starchcluster.gnu_parallel` script, where the final collation step was missing.

  - The `vcf2bed` script now accepts the `--do-not-split` option, which prints one BED element for all alternate alleles.

* Starch archival format and compression/extraction tools

  - Added duplicate- and nested-element flags in v2.1 of Starch metadata, which denote if a chromosome contains one or more duplicate and/or nested elements. BED files compressed with `starch` v2.5 or greater, or Starch archives updated with `starchcat` v2.5 or greater will include these values in the archive metadata. 

    The `unstarch` extraction tool offers `--has-duplicate` and `--has-nested` options to retrieve these flag values for a specified chromosome (or for all chromosomes).

  - Added `--is-starch` option to `unstarch` to test if specified input file is a Starch v1 or v2 archive.

  - Added bug fix for compressing BED files with `starch`, where the archive would not include the last element of the BED input, if the BED input lacked a trailing newline. The compression tools now include a routine for capturing the last line, if there is no newline.

* Documentation improvements

  - Remade some image assets throughout the documents to support Retina-grade displays