Explicit add linking to boost_system

{debugger}[GCC/4.9.2] GDB 7.8.2 (OK)

{toolchain} [iomkl/2015.01] (REVIEW)

{lang}[goolf/1.5.14] R 3.1.2 + deps (REVIEW)

{devel}[goolf/1.5.14] Qt 4.8.6 + deps (REVIEW)

{devel}[intel/2015a] Qt 4.8.6 + deps (REVIEW)

{devel} [intel-2015a] Likwid 3.1.2 (OK)

{lang}[goolf/1.5.14] Python 2.7.9 + deps (REVIEW)

[foss/2015a] Python 2.7.9 + deps (OK)

{tools}[foss/2015a,GCC,4.9.2] numactl 2.0.10 (OK)

{lang}[intel/2015a] R 3.1.2 + deps (OK)

{chem}[intel/2014b] CP2K 20131211 (OK)

style fix in comment w.r.t. Python extensions version update