Enlarge buffer used for file reads in `TPatcher`

[delphidabbler]

The current file read buffer size is only 4Kb - a size set back in 1999 when memory was much more scarce.

This can now safely be enlarged.

[delphidabbler]

Add command line option to change buffer size?

[delphidabbler]

Changed buffer to 1MiB as of commit 79f0965eb0357b05d949935eab97b700a973d211

[delphidabbler]

Add command line option to change buffer size?

Not fixed in this. Request opened as new issue #39.

[delphidabbler]

When testing prior to release of v1.0.0-beta.2 BPatch was failing to reconstruct the original file. This was tracked down to the new 1MiB file buffer size implemented at commit 79f0965eb0357b05d949935eab97b700a973d211.

The reason for this bug was not found, but reducing the buffer size to 64 KiB fixed the problem. This was fixed at commit d0e3f4e7bfcb6ba3ca6c70d98d88db8962745cff.