Fix broken </tt> tag on the clustering docs

There is a missing '<' in the clustering documentation for the
--id option [1] which makes the output look like this:

    –id can be used with –sparse/tt>.

This patch adds the missing symbol making it properly display
as:

    –id can be used with –sparse.

NOTE: This is a single character change better viewed with the
`--word-diff` option.

http://docs.graphlab.org/clustering.html#clustering_kmeans_id
Merge pull request #127 from batra-mlp-lab/master

ADMM and Bethe-ADMM
added a sanity check to verify graph has non zero nodes and edges
fixed a typo in rpc.dox
Merge pull request #128 from xunzheng/master

fixed a typo in rpc.dox
Temporary fix to bug where ncpus < nworkers. Happens when you set --ncpus to below #cores - 2
fixed a documentation error thanks to omer b
added a comment about normalization of pagerank to the doc
Merge pull request #130 from dbickson/master

Fixed some pagerank documentation error thanks to omer b
fix bug for oblivious and performance issue for random, grid and pds when parallel loading multiple graph files
wrong size of out_queue_locks in queued_fifo_scheduler.cpp
Merge pull request #132 from realstolz/wrong-size-fix

wrong size of out_queue_locks in queued_fifo_scheduler.cpp
added joel wellings environment variable for setting num of cores
Warp tutorial made coherent with basic tutorial
Merge pull request #134 from cerquide/warp_doc_fix

Warp tutorial made coherent with basic tutorial
typo fix
Merge pull request #135 from hupili/doc

some typo fix in docs. thanks hupili for fixing!
cap prediction values into [min, max]
fixed output in svd++
Merge branch 'master' of https://github.com/graphlab-code/graphlab