Conan

- Fixed bug with `short_paths` feature in windows.
- Improved error messages for non-valid `profile` text files.
- Remove downloaded tgz package files from remotes after decompress them.
- Fixed bug with `install --all` and `short_paths` feature

- Feature: Added profiles, as user predefined settings and environment variables (as CC and CXX
for compiler paths). They are stored in files in the conan cache, so they can be easily edited,
added, and shared. Use them with `$ conan install --profile=name`
- Feature: `short_paths` feature for Windows now also handle long paths for the final package,
in case that a user library has a very long final name, with nested subfolders.
- Feature: Added `tools.cpu_count()` as a helper to retrieve the number of cores, so it can be
used in concurrent builds
- Feature: Detects cycles in the dependency graph, and raise error instead of exhausting recursion
limits
- Feature: Conan learned the `--werror` option that will raise error and stop installation under
some cases treated as warnings otherwise: Duplicated dependencies, or dependencies conflicts
- Feature: New `env` generator that generates a text file with the environment variables defined
by dependencies, so it can be stored. Such file is parsed by `$ conan build` to be able to use
such environment variables for `self.deps_env_info` too, in the same way it uses the `txt`
generator to load variables for `self.deps_cpp_info`.
- Fix: Do not print progress bars when output is a file
- Fix: Improved the local conan search, using options too in the query `conan search -q option=value`
- Fix: Boto dependency updated to 2.43.0 (necessary for ArchLinux)
- Fix: Simplified the `conan package` command, removing unused and confusing options, and more
informative messages about errors and utility of this command.
- Fix: More fixes and improvements on `ConfigureEnvironment`, mainly for Windows
- Fix: Conan now does not generate a `conanbuildinfo.txt` file when doing `$ conan install <PkgRef>`
- Bug fix: Files of a package recipe are "touched" to update their timestamps to current time when
retrieved, otherwise some build systems as Ninja can have problems with them.
- Bug fix: `qmake` generator now uses quotes to handle paths with spaces
- Bug fix: Fixed `OSInfo` to return the short distro name instead of the long one.
- Bug fix: fixed transitivy of ``private` dependencies

This minor solves some problems with `ConfigureEnvironment`, mainly for Windows, but also fixes
other things:
- Fixed concatenation problems in Windows for several environment variables. Fixed problems with
path with spaces
- A batch file is created in Windows to be called, as `if defined` structures doesn't seem to
work in the command line.
- The `vcvars_command` from `tools` now checks the Visual Studio environment variable, if it is
already set, it will check it with the current project settings, throwing an error if not matching,
returning an empty command if matches.
- Added a `compile_flags` property to `ConfigureEnvironment`, to be passed in the command line
to the compiler, but not as environment variables
- Added `defines` to environment for nix systems, it was not being handled before
- Added new tests, compiling simple projects and diamond dependencies with cmake, cl (msvc), gcc (gcc in linux, mingw in win)
and clang (OSX), for a better coverage of the `ConfigureEnvironment` functionality.
- Fixed wrong `CPP_INCLUDE_PATH`, it is now `CPLUS_INCLUDE_PATH`