Remove use of update() in funccount

Hash map updates are not safe in recursive context. Change the
implementation of funccount to be read-only by converting
lookup_or_init() to lookup(). When run in interval mode, zero the counts
table instead of clearing it.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Add a helper to translate from kernel name to symbol. As part of this,
slightly refactor the ksym globals (which are internal implementation
and not part of the api) so that there is one array of tuples instead of
two arrays.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

It is sometimes useful to zero out the entries of table without erasing
the keys. Add a zero() function to make this easy.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Enforce limit of 1000 open [uk]probes

The number of open probes has bitten users already, so lets enforce a
limit with a meaningful(ish) message.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Prepare debian changelog for v0.1.8 tag

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Prepare deb build for nightly target

Add incremental release numbering for deb targets.
Tweak rpm release numbering as well.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Fix ubuntu kernel path typo is INSTALL.md

Update rpm build scripts and README

Print traceback only if verbose mode was requested

trace: trace function execution with custom format strings and filters

Remove the unused Dockerfiles.

Create two flavors of spec files, one which includes steps to build
clang from source and link against it, and one which assumes clang is
already available and just builds bcc. The former is more appropriate
for official packaging, the latter for nightly and quick builds.

Also, introduce a numbering scheme for nightly rpm files. The format
will be:
`libbcc-$latest_git_tag-g$latest_git_hash.x86_64.rpm`
as in:
`libbcc-0.1.7-g73c4d1a.x86_64.rpm`

Update the INSTALL.md to mention the RPMs
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>

Documentation and tcp4connect enhancements

tcpconnlat

Migrated killsnoop to bpf_perf_event

syncsnoop migrated to use bpf_perf_events