Build out lines when parsing html and holding >750 words in buffer (#73)

## Summary

* Build out lines for pages when holding over 750 buffered words
* Should fix issues with parsing long blocks of text causing memory
crashes

lib/Epub/Epub/ParsedText.h

@@ -2,11 +2,11 @@
 
 #include <EpdFontFamily.h>
 
-#include <cstdint>
 #include <functional>
 #include <list>
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "blocks/TextBlock.h"
 
@@ -18,6 +18,12 @@ class ParsedText {
   TextBlock::BLOCK_STYLE style;
   bool extraParagraphSpacing;
 
+  std::vector<size_t> computeLineBreaks(int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths) const;
+  void extractLine(size_t breakIndex, int pageWidth, int spaceWidth, const std::vector<uint16_t>& wordWidths,
+                   const std::vector<size_t>& lineBreakIndices,
+                   const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+  std::vector<uint16_t> calculateWordWidths(const GfxRenderer& renderer, int fontId);
+
  public:
   explicit ParsedText(const TextBlock::BLOCK_STYLE style, const bool extraParagraphSpacing)
       : style(style), extraParagraphSpacing(extraParagraphSpacing) {}
@@ -26,7 +32,9 @@ class ParsedText {
   void addWord(std::string word, EpdFontStyle fontStyle);
   void setStyle(const TextBlock::BLOCK_STYLE style) { this->style = style; }
   TextBlock::BLOCK_STYLE getStyle() const { return style; }
+  size_t size() const { return words.size(); }
   bool isEmpty() const { return words.empty(); }
   void layoutAndExtractLines(const GfxRenderer& renderer, int fontId, int horizontalMargin,
-                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine);
+                             const std::function<void(std::shared_ptr<TextBlock>)>& processLine,
+                             bool includeLastLine = true);
 };