core/store.h: Reordered file to group related functions better.
store.h: Fixed a typo.
store: Added sdb_store_expr_typed.

This function creates an expression which evaluates another expression in the
context of an object's sibling. The sibling is specified by type and refers to
a parent or child node of the specified type.
frontend/grammar: Added support for <obj_type> . <obj_expression>.

… where <obj_expression> may be an arbitrary expression accessing an object's
fields or attributes.
analyzer: Analyze expressions as well; validate typed expressions.

Also, added various tests for typed expressions.
Use stdbool.h's bool type instead of _Bool.

That'll work with C++ as well.
Bootstrap the build system for C++ as well.

That is, check CXX support for strict compiler flags.

Also, use all configured strict flags when checking for other strict flags.
This way, we detect problems when using flags that are not supported in C++
mode.
facter plugin: Added a plugin collecting local facter values.

The plugin uses libfacter from the cfacter project. libfacter is a C++
library, so the plugin is implemented in C++ as well using a small shim to
talk to SysDB.
Added documentation and sample configuration for the facter backend.