Fix itoa() for other than negative numbers

Previously it skipped one character in buffer even if there was no minus sign added.
Merge pull request #66 from weakset/master

Fix itoa() for other than negative numbers
Fix for partial TCPClient readings

Added total buffered size to compare offset
Update spark_wiring_tcpclient.h
Update spark_wiring_tcpclient.cpp
Control Jtag enabme seperate from DFU_BUILD_ENABLE
Added Support for building with CodeSourcery
Mising Defines from merge
Merge branch 'master' of https://github.com/spark/core-firmware
Update spark_wiring_tcpclient.h

I had 16 hard coded one place in my local code. Now it should work straight from Github base.
Updated README to mention dfu-utils version
Merge pull request #67 from weakset/master

Fix for missing readings with TCPClient
Merge pull request #69 from theicfire/master

Updated README to mention dfu-utils version
Merge pull request #68 from davids5/master

Allow the use of Jtag independent of DFU_BUILD Support for build with CodeSourcery
Merge branch 'master' into compile-staging