Fix time accounting on msp430 Series 5 MCU based platforms (wismote)

See https://github.com/contiki-os/contiki/pull/727 for explanation
Fix time accounting on TI EXP5438 MSP430x5438a experimenters board
er-coap (observe): fix possible duplicate value for observe option in GET response and subsequent notification

Currently, the observe value for a response to a GET observe request is always set to zero. That may cause the subsequent notification to have the same observe value. In fact, that happens every time an observable resource is observed for the first time (since the obs_counter is implicitly initialized to zero).
This patch fixes such a problem by setting the observe option value of responses to obs_counter (and then incrementing it).
Add SHT11 CoAP Resource and Activate Sensors for several CoAP Resources.
[cooja] Memory: Added get/setByteArray functions to Memory access class

Provides a cleaner interface to access memory as VarMemory already
contains variable name based get/setByteArray functions.
[cooja] Memory: Added add/removeMemoryMonitor functions

Provides a cleaner interface to access memory as VarMemory already
contains variable name based add/removeVarMonitor functions.
[cooja] interfaces/IPAddress: Indention cleanup
[cooja] interfaces/IPAddress: Added @Override annotations
[ccoja] Added new IPUtils class

Utility class to convert IPv4/IPv6 byte arrays to String representation.

* RFC5952-compliant IPv6 address shortening routine
[cooja] Get rid of all those redundant IP address to String functions

Commonly use the String representation functions of IPUtils.
[cooja] interfaces/IPAddress: Reimplementation of the IPAddress interface

New features:
* extended interface
* Shows all IPv6 addresses of a mote
* Shows link local IP in visualizer
* Reads IPs correctly from different memory layouts
Merge pull request #569 from ejoerns/pull-req/cooja-newip

[Cooja] Reimplementation of the IPAddress interface
Merge pull request #779 from PaulCorbalan/master

Add SHT11 CoAP Resource and Activate Sensors for CoAP Resources like Light, Battery.
Merge pull request #778 from alessandrelli/fix_duplicate_observe_value

er-coap (observe): fix possible duplicate value for observe option
Merge pull request #777 from atiselsts/msp430f5xxx_timing_fixes

Fix time accounting on msp430 Series 5 MCU based platforms
[cooja] plugins/VariableWatcher: Added @Override annotations
[cooja] plugins/VariableWatcher: Added Combo as name suffix for JComboBoxes
[cooja] plugins/VariableWatcher: Enums for ComboBoxes and new one for display format

Allows to choose between var types (byte, short, int, long) and display
types (char, decimal, hex)
[cooja] plugins/VariableWatcher: Implemented formatted output for value fields
[cooja] plugins/VariableWatcher: Replace varName KeyListener by DocumentListener as only content changes change validation state of varName
Modify foreground color of varName instead of background color because some LookAndFeels do not support colored backgrounds.