[FIX] Add missing EPLDLLEXPORT macro

Add missing EPLDLLEXPORT macro for function EplApiSetAsndForward().

Change-Id: I8db6432de9dbb9cfef7ce1ffe40bc936196046dc
[FIX] Trigger loss of Soc error event only once per cycle

Implement flags to guard the loss of Soc error event.

Guard mechanism procedure:
1. Set flag fLossReported when a loss is reported to the
   error handler.
2. Set flag fTimeoutOccurred when the timeout event was
   thrown for this Soc loss. As every loss of Soc generates
   a timeout this flag is used to detect two or more
   loss of Soc's in a row.
3. Reset the flags on reception of a valid Soc.


Change-Id: I1d1750f246ff7f8a6d6ed962d2217aaa25c34383
[FIX] Add missing extern 'C' declaration.

Change-Id: I5e53cb30c4c0b3abf58dac513c8b192a1d387e97
[FIX] Fix ASnd frame filter setup

ASnd frames are not only restricted to the specified multicast MAC
address. Also uni- and broadcast addressing must be supported by
POWERLINK nodes. Therefore, the ASnd Rx frame filter is revised ignoring
the destination MAC address, instead check the EtherType and the POWERLINK
message type.


Change-Id: I3961558a2b3a12b084cbe8d69edecf32b26caf91
[FIX] Fix PReq frame size check

Remove frame format error post for received PReq frame with size exceeding
the calculated frame size limit (object 0x1F98.4 / PreqActPayloadLimit).
Instead the PReq payload is directly compared with the configured frame
size limit (PreqActPayloadLimit). This fixes issues with MNs that transmit
larger PReq frames than necessary.

Change-Id: I8ab2bd013e04b48669a752f72b2ded35e868cc75
[FIX] Fix SDO command invalid handle error in CFM

The CFM node event process function may only abort and undefine a valid
SDO command connection.

Change-Id: If2b7f42858b3bcc1a70df94bdca4ef5dead67bd6
[FIX] Incorrectly declared variable

Non-critical fix.

Change-Id: I1a837edaa3b2049860acb80ab689d9c7b484cd5d
Merge branch 'develop-1.8.5' of https://github.com/jbaumgar/openPOWERLINK_systec