Snapshots (#38)

* Add Olimex Joystick

* Fix extra warnings

* z80 load and save

* First running version

* Sound support

* Store sound and display state state

* Maintain program specific data

* Update Readme

* Add version to load

* Build checks

* Build improvements

* version error

* Save complete sound state

* Select resolution

* Tidy F8 exit

* Unnecessary cast

* uf2 and excludes

* DEscribe snapshot file format

* Snall Readme changes

* Clarify the effect of F1

* Reduce cursor speed in menu

* Clean directory

* Missing uf2

* Update build and info

* add comma

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Co-authored-by: ikjordan <iankjordan@gmail.com>

RP2350 and sdk 2.0 Support (#36)

* Updates for SDK 2.0

* Add rp2350 build

* Add FLASH_LED option

also correct OVER_VOLT description

* Update launch and Readme

* Add new uf2

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Co-authored-by: ikjordan <iankjordan@gmail.com>

Zx80, load and Save, TV sound (#34)

* zx80 and vsync sound

* Test wav save

* improve beep generation

* Correct silence

* Testing

* Fix race

* add uf2

* audio sync & z80 chroma offset

* Update uf2

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Co-authored-by: ikjordan <iankjordan@gmail.com>

Picozxreal (#33)

* start picozxreal

* Refactor

* First pass Bootsel

* Update PicoDVI

* No serial for picozxreal

* Testing zxpico with LCD

* Testing picozx variants

* Update Readme

* Update Readme

* Readme update

* Update Readme for back power

* Add more tested applications

* Add 3DMM image

* Update images

* Correct link

* add image credit

* SPI bus speed

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Co-authored-by: ikjordan <iankjordan@gmail.com>

Merge pull request #28 from ikjordan/new_picodvi

New picodvi

Merge pull request #24 from ikjordan/hdmimerge

Hdmimerge

uf2

optional hardware_pwm

Update readme and uf2