Fixed loading of type library, added 2 Tcl files that are part of the fix.

* type library is loaded directly within initialization function
* DLL must be in current working directory while "load" is called
* package loading mechanism (pkgIndex.tcl) does this automatically on a
    "package require activexscripthost" command
First character of error messages lower case (no code change).
Comments describing fields of the AXSH_EngineState structure (no code change).
Tiny formatting change (no code change).
Removed unused local variable and corrected return value in GetItemInfo().
The "parse" subcommand of an engine can now set flags for ParseScriptText().

* options "-visible", "-expression" and "-persistent" can be passed to "parse"
* last argument to "parse" is always the script to parse
* parse result (when -expression is set) yet to be written as Tcl interp result
Correctly handle parse result (VARIANT), try to convert result to Tcl result.

* can convert many VARIANT types to Tcl objects: VT_EMPTY, VT_I2, VT_I4, VT_R4,
    VT_R8, VT_BSTR, VT_BOOL, VT_I1, VT_UI1, VT_UI2, VT_UI4, VT_INT, VT_UINT
* types that cannot be converted: any VT_ARRAY type, any VT_BYREF type,
    VT_CY (currency), VT_DATE, VT_DISPATCH, VT_ERROR, VT_VARIANT, VT_UNKNOWN,
    VT_DECIMAL, VT_RECORD
Use Tcl keyword lookup for "parse" engine subcommand options.
Call ParseScriptText() with result pointer NULL when not evaluating expression.

* at least the VBScript engine doesn't seem to like a non-NULL result pointer
    when the SCRIPTTEXT_ISEXPRESSION flag is not set
* scriptlet is then evaluated immediately even when the script state is
    not SCRIPTSTATE_CONNECTED or SCRIPTSTATE_STARTED
* this is not what we want
Stub code for checking EXCEPINFO returned by ParseScriptText().