userspace/libsinsp/filter: make next_operand return vector<char>

Modify sinsp_filter::next_operand to handle operand which contains
the NUL terminator.
userspace/libsinsp/filter*: modify parse_filter_value to accept len

When the filter value is binary, we need to pass the length of the
value.
userspace/libsinsp/filter*: extend rawval_to_string to accept PT_BYTEBUF
userspace/libsinsp/filter*: evt.buffer return raw_value when m_is_compare
userspace/libsinsp/filterchecks: some refactoring
userspace/libsinsp/filter*: transform evt.buffer in PT_BYTEBUF
userspace/libsinsp: remove old code
userspace: remove some trailing whitespace
userspace/libsinsp/parsers.cpp: filter out events about sysdig digs sysdig
userspace: add option to enable sysdig to capture events about itself
userspace/libsinsp/parsers: fix compile error on windows
[53] Build for Solaris

Adds the necessary code splits for GNU make and SunOS -l flags into
the CMakeLists.

Changes the pragma rules for SunOS g++ (which do not support pop)

Also adds some minor include file preprocessor branches with __sun
tests.
[28] Complete quoting for parameters of some CMake commands

Adds quotes where applicable for variables inside of the CmakeLists
files
fix error message so that it is reachable and matches other checks in kernel driver
Merge pull request #85 from kristopolous/53-build-for-solaris

[53] Build for Solaris
Merge pull request #84 from teancom/master

fix error message so that it is reachable
Merge pull request #83 from kristopolous/28-complete-quoting-for-parameters-of-some-cmake-commands

[28] Complete quoting for parameters of some CMake commands. fixes #28
userspace/libsinsp/parsers: cache the current pid and get_thread_info
userspace/libsinsp: get thread info about a event only for live capture
Added spy_port.lua