Feature/cmake build system

[linsmod]

Summary

This PR adds a complete modern CMake build system to improved developer experience.

Features

• Modern build system using CMake 3.10+
• Complete feature support - PNG, JPEG, GIF, SVG, WebP, TLS, IPv6, XEmbed
• Development builds - Run directly from build directory
• Full installation - Installs to standard system locations
• Uninstall support - Clean removal of all installed files

Build Targets

All 17 targets build successfully:

• [dillo] Main browser executable
• dpid_bin - DPI daemon (installed as dpid)
• dpidc - DPI client
• dilloc - Control socket client
• 8 DPI plugins for different protocols
• 5 supporting libraries

Usage

# Build
cmake -B build -DCMAKE_BUILD_TYPE=Debug
cmake --build build --parallel 4

# Install
sudo cmake --install build

# Uninstall
sudo cmake --build build --target uninstall