various minor bugfixes + warningfixes (#2878)

* fix unclosed file descriptors

* remove various compiler warnings

sometimes it was only ambiguous indentation, sometimes bugs were fixed:

- forgotten `break;` instructions or `fallthrough` annotations:
  - src/ANT/ANTChannel.cpp
  - src/Charts/CriticalPowerWindow.cpp
  - src/Charts/MUPlot.cpp
  - src/Core/DataFilter.cpp
  - src/FileIO/RideFileCache.cpp
  - src/FileIO/RideFileCommand.cpp
  - src/Train/DialWindow.cpp
- forgotten braces:
  - lmfit/lmmin.c
  - src/FileIO/XDataDialog.cpp
- test on the wrong variables:
  - src/Gui/Pages.cpp
- wrong parenthesis
  - src/Charts/CPPlot.cpp
- missing macro argument
  - src/Cloud/WithingsDownload.cpp
- missing `return;` statement
  - src/Cloud/Xert.cpp
- unused variables
  - src/Gui/DiarySidebar.cpp
- unclear indentation
  - src/Core/RideItem.cpp
  - src/FileIO/BinRideFile.cpp
  - src/Metrics/PaceZones.cpp
  - src/Metrics/RideMetadata.cpp
  - src/Metrics/Zones.cpp

* remove unnecessary Leaf::Parameters enum value from data filters

lists of parameters don't exist as such outside of the parser, and have
no business using the same type `Leaf` as complete terms anyway

* remove unnecessary argument

`leaf1.print(leaf2,...)` would print `leaf2` and completely ignore
`leaf1`, so now `leaf2.print(...)` is used instead

qwt/examples/cpuplot/cpustat.cpp

@@ -216,5 +216,6 @@ void CpuStat::lookUp( double values[NValues] ) const
             }
         }
         while( !textStream.atEnd() );
+        file.close();
     }
 }