Fix #237, Update to remove global pipename and data structure. Update cmd to increment command counter. Update SAMPLE_APP_ProcessCmd to have only 1 return.

Describe the contribution
A clear and concise description of what the contribution is.

• Include explicitly what issue it addresses [e.g. Fixes #X]

Testing performed
Steps taken to test the contribution:

1. Make SIMULATION=native install

2. Run Test

3. Make ENABLE_UNIT_TESTS=true SIMULATION=native

4. Make test

5. make lcov

Expected behavior changes
A clear and concise description of how this contribution will change behavior and level of impact.

• API Change: xxx (if applicable)
• Behavior Change: xxx (if applicable)
• Or no impact to behavior

System(s) tested on

• Hardware: [e.g. PC, SP0, MCP750]
• OS: [e.g. Ubuntu 18.04, RTEMS 4.11, VxWorks 6.9]
• Versions: [e.g. cFE 6.6, OSAL 4.2, PSP 1.3 for mcp750, any related apps or tools]

Additional context
Add any other context about the contribution here.

Third party code
If included, identify any third party code and provide text file of license

Contributor Info - All information REQUIRED for consideration of pull request
Full name and company/organization/center of all contributors ("Personal" if individual work)

• If NASA Civil Servant Employee or GSFC Contractor on SES II
  • Address/email/phone and contract/task information (if applicable) must be on file
• Else if Company
  • HAND SIGNED Company CLA must be on file (once per release): Company CLA
• Else if Individual
  • HAND SIGNED Individual CLA must be on file (once per release): Individual CLA
    Anh Van, GSFC