Finished implementing more vision functionalities from Pi CPU

New Pi Vision blocks:
1. Face Recognition
2. Object Detection
3. Image Classification
4. Draw Image Classification

Known issues:

1. When Initialize Vision block of Pi are used together with the OAKD Initialize block, there is no mechanism to
determine which one to display in the preview window.
2. When using USB/CSI camera on Pi are use with OAKD vision block, there is no mechanism to check if any OAKD nodes are
missing.

Author: michaelhwn

examples/cait/example_face_detection.cait

@@ -1,4 +1,4 @@
 scale: 0.8212667765397554
 scroll_x: -61.67318351780028
 scroll_y: 4.639316482199661
-<xml xmlns="https://developers.google.com/blockly/xml"><variables><variable id="ozm3`BWmay[2%wV1c{d3">face</variable></variables><block type="setup_block" id="3y3(Oty~zJghUWY*.yHe" x="140" y="60"><statement name="init_blocks"><block type="init_vision" id="eh^A$/PY+$Zad37K[c86"><statement name="oakd_statements"><block type="add_pipeline_node" id="Y]u|/VOY37OCHQ*XXd~;"><field name="node">rgb</field><next><block type="add_pipeline_node" id="FTDF-8E7Lf(8}C{i4~6y"><field name="node">face_detection</field></block></next></block></statement></block></statement></block><block type="main_block" id="R`/=?RO9k*(I88a?2%0[" x="140" y="380"><statement name="main_blocks"><block type="controls_whileUntil" id="oPwT{]tY(Yr^csVJ9{TW"><field name="MODE">WHILE</field><value name="BOOL"><block type="logic_boolean" id="fiJSa*clHD25tCeVg]E("><field name="BOOL">TRUE</field></block></value><statement name="DO"><block type="variables_set" id=",W/SV0wdu7`^^sBA1j)8"><field name="VAR" id="ozm3`BWmay[2%wV1c{d3">face</field><value name="VALUE"><block type="vision_detect_face" id="~GmsH/ZpgW-6}vI!KK%N"/></value><next><block type="vision_draw_detected_face" id="%5QX8`MEQY3o$!CNeGv2"><value name="face"><block type="variables_get" id="CK456,SW~|4XpzE#1`c8"><field name="VAR" id="ozm3`BWmay[2%wV1c{d3">face</field></block></value></block></next></block></statement></block></statement></block></xml>
+<xml xmlns="https://developers.google.com/blockly/xml"><variables><variable id="ozm3`BWmay[2%wV1c{d3">face</variable></variables><block type="setup_block" id="3y3(Oty~zJghUWY*.yHe" x="140" y="60"><statement name="init_blocks"><block type="init_vision" id="eh^A$/PY+$Zad37K[c86"><statement name="oakd_statements"><block type="add_pipeline_node" id="Y]u|/VOY37OCHQ*XXd~;"><field name="node">rgb</field><next><block type="add_pipeline_node" id="FTDF-8E7Lf(8}C{i4~6y"><field name="node">face_detection</field></block></next></block></statement></block></statement></block><block type="main_block" id="R`/=?RO9k*(I88a?2%0[" x="140" y="380"><statement name="main_blocks"><block type="controls_whileUntil" id="oPwT{]tY(Yr^csVJ9{TW"><field name="MODE">WHILE</field><value name="BOOL"><block type="logic_boolean" id="fiJSa*clHD25tCeVg]E("><field name="BOOL">TRUE</field></block></value><statement name="DO"><block type="variables_set" id=",W/SV0wdu7`^^sBA1j)8"><field name="VAR" id="ozm3`BWmay[2%wV1c{d3">face</field><value name="VALUE"><block type="vision_detect_face" id="~GmsH/ZpgW-6}vI!KK%N"/></value><next><block type="vision_draw_detected_face" id="%5QX8`MEQY3o$!CNeGv2"><value name="face"><block type="variables_get" id="CK456,SW~|4XpzE#1`c8"><field name="VAR" id="ozm3`BWmay[2%wV1c{d3">face</field></block></value></block></next></block></statement></block></statement></block></xml>