Lower data size used in test_hdfs.thread_allow to run on TravisCI
Fix run_wordcount_* scripts

This commit makes them work with both the 'hdfs' and 'hadoop fs'
commands, and it removes the unix-like options that were being passed to
'hdfs' (the 'hadoop dfs' command doesn't understand them)
If HADOOP_BIN is defined, add it to the PATH in TravisCI set-up
Since they're identical, remove duplicate config directories for 2.2 and 2.4
For Travis, set mapred.task.timeout to one minute
If HADOOP_BIN defined by installation, then add it to the PATH
Added HADOOP_BIN & HADOOP_SBIN to PATH
Lower the acceptable count threshold in thread test to 5

The tests were sometimes failing on TravisCI (slower machines) with
counts below 100.  A test where we left the GIL locked showed that the
counter value doesn't change at all across calls, so in theory even an
increment of 1 would demonstrate that the mechanism is working.
Set the PYTHONPATH on hadoop-env.sh
Explicit PYTHONPATH in the travis environment
Fixed PATH on hadoop_env.sh
Reactived virtualenv after the python-all-dev installation
PYTHONPATH in hadoop_env.sh is equal to the travis PYTHONPATH
Fixed the syntax of the hdfs command in run_wordcount_* scripts of pydoop_submit examples
Added missing 2.4.1 hadoop pipes sources
Merge pull request #47 from kikkomep/develop

Travis configuration fixes + other minor fixes