Reimplement parseopt which parses arguments given as a sequence of strings, not single string.

tests/system/params.nim

@@ -0,0 +1,17 @@
+import os
+import osproc
+import parseopt
+import sequtils
+
+let argv = commandLineParams()
+
+if argv == @[]:
+  # this won't work with spaces
+  assert execShellCmd(getAppFilename() & " \"foo bar\" --aa:bar --ab -c --a[baz]:doo") == 0
+else:
+  let f = toSeq(getopt())
+  echo f.repr
+  assert f[0].kind == cmdArgument and f[0].key == "foo bar" and f[0].val == ""
+  assert f[1].kind == cmdLongOption and f[1].key == "aa" and f[1].val == "bar"
+  assert f[2].kind == cmdLongOption and f[2].key == "ab" and f[2].val == ""
+  assert f[3].kind == cmdShortOption and f[3].key == "c" and f[3].val == ""