pre-purging before checking to facilitate long do chains

source files in the `compile` key of `module_info/1` so `rebar cover`
struggles locating source in some instances. in these cases a warning
is printed and crappy coverage info is written rather than none at all

`rebar.config` or via the `-c\--cover` flag given to the appropriate
task) from the `eunit` and `ct` tasks and add a `cover` task to
write coverage analysis to disk

make base_dir for a run include the profiles in path, link to shared dep

Some free tests from a debugging session

The session was unfruitful, but I guess the tests were not necessarily

don't replace non-string list with empty list in profile merge

Documentation is maintained on www.rebar3.org

reset state between tasks run with `do`

has the same outcome as `rebar3 foo && rebar3 bar && rebar3 baz`

fixes #191

Port env var expension fix from rebar2

add edoc provider

Support mercurial (hg) dependencies

See https://github.com/rebar/rebar/pull/458

remove old info function from install_deps, it is a bare provider

Fix crash on non-git source deps in deps provider

The 'element(1, ..)' guard would always fail and cause crashes.

profiles: combine lists of values for conflicting config options

We can use 3.0.0 when we're done.

Upgrade pkg

- Track level of packages properly, they're not level 0 anymore (this
  could yield an issue where a src dep takes precedence over a pkg dep)
- Proper stable sort of vertices in the digraph module
- PkgDeps no longer 'see themselves' when fetching and upgrading after
  locking themselves
- Pkg Locks are added to pkg deps rather than source deps
- Updating test cases to support pkg mocking on top of src mocking

Fix lock merging for nonexistant lock files.

basic profile deps tests

output hook stdout and don't add extra newline