See comment for more information. This commit also adds support
for an environment variable so that users have a workaround
when Nimble cannot find the Nim stdlib.
* PackageInfo objects are now cached because NimScript evaluation is expensive.
* before/after hooks now return `true` by default.
* Bugfix: when hooks weren't found Nimble would still think that a hook told it
to skip an action.
* PackageInfo now includes info about which hooks are defined to prevent
unnecessary execution of those hooks.
* Probably more.
* Moved package info reading procedures to a packageparser module. This is to prevent recu
rsive dependencies between nimscriptsupport and packageinfo modules.
* Passed the Options object to all procedures which read package info (necessary for nimscriptsupport module, to find the path of the nimscriptapi module)
* Introduced an ``isInstalled`` field to the ``PackageInfo`` type. This is a bug fix for g
etRealDir: it no longer uses the ``src`` field in the path it returns for installed packag
es' PackageInfo objects.
* Improved error reporting from NimScript evaluator.
* Renamed compiler/options import to ``compiler_options`` in ``nimscriptsupport`` module.
* Backward compatibility for .babel packages in getNameVersion proc.
* Introduced a getInstalledPkgsMin procedure which does not read package info, but only pr
ovides minimal info instead.
* setCommand "nop" no longer needed.
* Recursive setCommand supported.
* Explicit execTask procedure which executes the task explicitly instead of setting global compiler variables.
