bcc release v0.12.0

the main changes from v0.11.0 to v0.12.0 tag:
  * Support for kernel up to 5.4
  * klockstat tool to track kernel mutex lock statistics
  * cmake option CMAKE_USE_LIBBPF_PACKAGE to build a bcc shared library
    linking with distro libbpf_static.a
  * new map.lookup_or_try_init() API to remove hidden return in
    map.lookup_or_init()
  * BPF_ARRAY_OF_MAPS and BPF_HASH_OF_MAPS support
  * support symbol offset for uprobe in both C++ and python API,
    kprobe already has the support
  * bug fixes for trace.py, tcpretrans.py, runqslower.py, etc.

bcc release v0.11.0

the main changes from v0.10.0 to v0.11.0 tag:
  * Support for kernel up to 5.3
  * Corresponding libbpf submodule release is v0.0.5
  * Fix USDT issue with multi-threaded applications
  * Fixed the early return behavior of lookup_or_init
  * Support for nic hardware offload
  * Fixed and Enabled Travis CI
  * A lot of tools change with added new options, etc.

Initial tag

Merge pull request #29 from iovisor/bblanco_dev

Add simple single file example