jw.build.cmds: Move build.cmds -> cmds.projects

Reorganize the Python module structure. Placing the command classes under jw.cmds.projects instead of jw.build.cmds will allow to add a nested command structure, with the current commands, being mostly related to building software, found below a "projects" toplevel command.
Other conceivable commands could be "package" for packaging, or "distro" for commands wrapping the distribution's package manager.
Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/cmds/projects/CmdCheck.py

@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+
+from argparse import Namespace, ArgumentParser
+
+from ..Cmd import Cmd
+
+class CmdCheck(Cmd): # export
+
+    def __init__(self) -> None:
+        super().__init__('check', help='Check for circular dependencies between given modules')
+
+    def add_arguments(self, parser: ArgumentParser) -> None:
+        super().add_arguments(parser)
+        parser.add_argument('module', nargs='*', help='Modules')
+        parser.add_argument('-f', '--flavour', nargs='?', default = 'build')
+
+    def _run(self, args: Namespace) -> None:
+        graph = {}
+        path = []
+        self.app.read_dep_graph(args.module, args.flavour, graph)
+        unvisited = list(graph.keys())
+        temp = set()
+        while len(unvisited) != 0:
+            m = unvisited[0]
+            self.app.debug('Checking circular dependency of', m)
+            last = self.app.check_circular_deps(m, args.flavour, self.app.flip_graph(graph), unvisited, temp, path)
+            if last is not None:
+                self.app.debug('Found circular dependency below', m, ', last is', last)
+                print('Found circular dependency in flavour', args.flavour, ':', ' -> '.join(path))
+                exit(1)
+        print('No circular dependency found for flavour', args.flavour, ' in modules:',
+                ' '.join(args.module))
+        exit(0)