Gambas 3.7.1

[DEVELOPMENT ENVIRONMENT]
* BUG: Create the example directory if it does not exist when installing a
  non-example software having the 'example' tag.
* BUG: Removing a connection now removes the template file too.
* BUG: Remove a debugging message.
* NEW: Add an 'Installed softwares' button in the welcome dialog
* NEW: Always center the farm client window.

[INTERPRETER]
* BUG: Stream read ahead does not have to wait for the descriptor to be
  ready for reading.
* BUG: Do not read ahead file descriptors ready to read opened using the
  ".xx" special name.
* BUG: Shell$() now quotes quotes correctly.

[GB.DB.MYSQL]
* BUG: Don't crash when removing something from the metadata cache.

[GB.DB.SQLITE3]
* BUG: Detect primary key only with 'table_info' pragma. Consequently,
  fields declared as "INTEGER" will not be incorreclty taken as a default
  primary key anymore.

[GB.GTK]
* BUG: Fix a crash when calling Dialog.SaveFile() with a void Dialog.Path.
* BUG: TextBox: Setting the Pos property during a KeyPress event now works
  in all cases.

[GB.GTK3]
* BUG: Fix a crash when calling Dialog.SaveFile() with a void Dialog.Path.
* BUG: TextBox: Setting the Pos property during a KeyPress event now works
  in all cases.

[GB.REPORT2]
* BUG: Remove a bug on drawing grayscale preview in ReportView.
* BUG: Restore the report scaling after drawing in the DocumentView.
* BUG: Replace deprecated Image.Gray() by Image.Desaturate().
* BUG: Refresh the print button icon correctly.